TRANSPORTATION MODEL
Introduction
• The transportation problem is a special form of the general linear programming technique called the network flow problems.
• Networks are activities or jobs to be performed which can be represented by joining one start event to one end event.
Example of a network
End
Activity
Start
Transportation Problem Defined
• Transportation problem involves the distribution of goods from sources of supply (e.g. factories, warehouses) to a number of destinations of demand (e.g. retail – shops)
• Usually, the capacity of goods at each source and the requirements or demands for the goods at each destination are given or known.
Developing A Transportation Table
Example
ABC Office Supplier has three depots located in various towns. It receives order for a total of 15 special filing cabinets from four customers.
Customer Order
A 3
B 3
C 4
D 5
Total 15
In total the available filing cabinets in three depots are
Depot Available
X 2
Y 6
Z 7
Total 15
The management wishes to minimize delivery costs by dispatching the filing cabinets from appropriate depot for each customer. The transportation costs from each depot to each customer per filing cabinet are given in Table 1.
Table 1 - Transportation Costs per Cabinet for ABC Office Supplier
To Requirements (customer)
From A B C D
Depot X RM13 RM11 RM15 RM20
Depot Y 17 14 12 13
Depot Z 18 18 15 12
Our first step is setting-up a transportation table i.e to summarize all relevant data and to keep track of algorithm computations. Using the above information, the transportation table is shown in Table 2.
Table 2 – Transportation Table for ABC Office Supplier
To
From
Customer
A
Customer
B
Customer
C
Customer
D
Depot
Available
Depot X
13
11
15
20
2
Depot Y
17
14
12
13
6
Depot Z
18
18
15
12
7
Customer
Requirements
3
3
4
5
15
Step-by-step explanation
1. we starts in the upper-left hand corner, distribute 2 (supply capacity) units cabinet to customer A. Since depot X has only 2 units cabinet available and demand (requirement) from customer A is 3 units, move down to the second row in the same column.
2. Now, deliver 1 unit cabinet (availability 6 units) to customer A. they will make customer A has 3 units cabinet (2 from depot X and 1 from depot Y). Move to the next column and deliver 3 units to customer B (demand is 3 units). Now depot Y has 2 units left, move to the right to the next column and deliver 2 units to customer. Move down to the third row in the same column.
3. Since customer C requires 4 units, deliver 2 units from depot Z (2 units is from depot Y). At this stage there are 5 units available, deliver all 5 units to customer D (demand is 5 units).
Now when the initial feasible solution have been determine, we can calculate the initial transportation cost.
Stepping-Stone Method
• This is a method that moves an initial feasible solution to an optimal solution.
• Before we applied this method to the problem, we must make sure that the transportation routes from our table must have : the number of occupied routes (or squares) must always be equal to tone less than the sum of the number of rows plus the number of columns.
• Occupied transportation routes (squares) = number rows + number columns – 1
Testing The Solution For Possible Improvement
The test for each square is as follows:
a. Select an unused square to be evaluated
b. Beginning at this square, trace a closed path back to the original square via squares that are currently being used, moving with only horizontal and vertical only.
c. Beginning with a plus (+) sign at the unused square, place alternate minus (-) signs and plus signs on each corner square of the closed path.
d. Calculate an improvement index by adding together the unit cost found in each square containing a minus sign.
e. Repeat steps (a) to (d) until an improvement index has been calculated for all unused squares.
f. If all indices computed are greater than or equal to zero an optimal solution has been reached. If not, it is possible to improve the current solution and decrease the total transportation costs.
To Improve the Solution
• Every negative amount index computed means that the total transportation costs could be decreased by the amount if 1 unit of product used the route.
• If there were more than one negative index, choose the route with the largest negative index.
• Now to determine the maximum quantity that can be transport using this route we do the following:
Refer to the closed path of plus and minus sign on this route.
Select the smallest number found in those squares containing minus signs.
Add this number to all squares with plus signs on the closed path and subtract from all squares on the path with minus signs.
To
From
Customer
A
Customer
B
Customer
C
Customer
D
Depot
Available
Depot X
2 13
11
15
20
2
Depot Y
1 17
3 14
2 12
13
6
Depot Z
18
18
2 15
5 12
7
Customer
Requirements
3
3
4
5
15
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
Depot X - Customer B = +11 -14 +17 -13
= +1
Depot X - Customer C = +15 -12 +17 -13
= +7
Depot X - Customer D = +20 -12 +15 -12 +17 -13
= +15
Depot Y - Customer D = +13 -12 +15 -12
= +4
Depot Z - Customer A = +18 -15 +12 -17
= -2
Depot Z - Customer B = +18 -15 +12 -14
= +1
Total Transportation Cost = (2 X 13) + (17X 1) + (14 X 3) + (2 X 12) + (15 X 2) + (12 X 5)
= 26 + 17 +42 +24 +30 +60
= RM199
To
From
Customer
A
Customer
B
Customer
C
Customer
D
Depot
Available
Depot X
2 13
11
15
20
2
Depot Y
17
3 14
3 12
13
6
Depot Z
1 18
18
1 15
5 12
7
Customer
Requirements
3
3
4
5
15
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
Depot X - Customer B = +11 -13 +18 -15 +12 -14
= -1
Depot X - Customer C = +15 -13 +18 -15
= +5
Depot X - Customer D = +20 -12 +18 -13
= +13
Depot Y - Customer A = +17 -12 +15 -18
= +2
Depot Y - Customer D = +13 -12 +15 -12
= +4
Depot Z - Customer B = +18 -15 +12 -14
= +1
Total Transportation Cost = (2 X 13) + (14 X 3) + (3 X 12) + (18 X 1) + (15 X 1) + (12 X 5)
= 26 + 42 + 36 + 18 + 15 + 60
= RM197
To
From
Customer
A
Customer
B
Customer
C
Customer
D
Depot
Available
Depot X
1 13
1 11
15
20
2
Depot Y
17
2 14
4 12
13
6
Depot Z
2 18
18
15
5 12
7
Customer
Requirements
3
3
4
5
15
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
Depot X - Customer c = +15 -12 +14 -11
= +6
Depot X - Customer D = +20 -12 +18 -13
= +13
Depot Y - Customer A = +17 -14 +11 -13
= +1
Depot Y - Customer D = +13 -12 +18 -13 +11 -14
= +3
Depot Z - Customer B = +18 -18 +13 -11
= +2
Depot Z - Customer B = +15 -18 +13 -11 +14 -12
= +1
Total Transportation Cost = (1 X 13) + (11 X 1) + (2 X 14) + (12 X 4) + (18 X 2) + (12 X 5)
= 13 + 11 + 28 + 28 + 36 + 60
= RM176
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
EXERCISE – CHAPTER 8
Question
The Giant Farmer Company process cement, which it stocks in various warehouse. The market research study provided the following data:
Table 1 : Warehouse
Warehouse Capacities (tones)
W 250
X 400
Y 300
Z 200
Table 2 : Demand
A 400
B 150
C 600
Table 3 : Shipping cost per tones
From W to A : 67 From Y to A : 29
From W to B : 42 From Y to B : 47
From W to C : 51 From Y to C : 60
From X to A : 61 From Z to A : 43
From X to B : 24 From Z to B : 31
From X to C : 39 From Z to C : 42
Use the Northwest – Corner Approach Method to find the shipping that minimize shipping cost
To
From
Customer
A
Customer
B
Customer
C
Warehouse
W
250 67
42
51
250
X
150 61
150 24
100 39
400
Y
29
47
300 60
300
Z
43
31
200 42
200
Customer
Requirements
400
150
600
1150
Occupied transportation routes = M + N - 1
= 4 + 3 – 1
= 6
Index
Depot W - Customer B = +42 -24 +61 -67
= +12
Depot W- Customer C = +51 -39 +61 -67
= +6
Depot Y - Customer A = +29 -60 +39 -61
= -53
Depot Y - Customer B = +47 -60 +39 -24
= +2
Depot Z - Customer A = +43 -42 +39 -61
= -21
Depot Z - Customer B = +31 -42 +39 -24
= +4
Total Transportation Cost = (250 X 67) + (150X 61) + (150 X 24) + (100 X 39) + (300 X 60) + (200 X 42)
= 16750 + 9150 + 9750 + 3900 + 18000 + 8400
= RM65950
To
From
Customer
A
Customer
B
Customer
C
Warehouse
W
250 67
42
51
250
X
61
150 24
250 39
400
Y
150 29
47
150 60
300
Z
43
31
200 42
200
Customer
Requirements
150
150
600
1150
Occupied transportation routes = M + N - 1
= 4 + 3 – 1
= 6
Index
Depot W - Customer B = +42 -67 +29 -60 +39 -24
= -41
Depot W - Customer C = +51 -67 +29 -60
= -47
Depot XY - Customer A = +61 -39 +60 -29
= +53
Depot Y - Customer B = +47 -60 +39 -24
= +2
Depot Z - Customer A = +43 -42 +60 -29
= +32
Depot Z - Customer B = +31 -42 +39 -24
= +4
Total Transportation Cost = (250 X 67) + (150X 24) + (250 X 39) + (150 X 29) + (150 X 60 + (200 X 42)
= 16750 + 3600 + 9750 + 4350 + 9000 + 8400
= RM51850
To
From
Customer
A
Customer
B
Customer
C
Warehouse
W
100 67
42
150 51
250
X
61
150 24
250 39
400
Y
300 29
47
60
300
Z
43
31
200 42
200
Customer
Requirements
150
150
600
1150
Occupied transportation routes = M + N - 1
= 4 + 3 – 1
= 6
Index
Depot W - Customer B = +42 -51 +39 -24
= +6
Depot X - Customer A = +61 -39 +51 -67
= +6
Depot Y - Customer B = +47 -24 +39 -51 +67 -29
= +49
Depot Y - Customer B = +60 -51 +67 -29
= +47
Depot Z - Customer A = +43 -42 +51 -67
= -15
Depot Z - Customer B = +31 -42 +39 -24
= +4
Total Transportation Cost = (100 X 67) + (150X 51) + (150 X 24) + (250 X 39) + (300 X 29) + (200 X 42)
= 6700 + 7650 + 3600 + 9750 + 8700 + 8400
= RM44800
To
From
Customer
A
Customer
B
Customer
C
Warehouse
W
67
42
250 51
250
X
61
150 24
250 39
400
Y
300 29
47
60
300
Z
100 43
31
100 42
200
Customer
Requirements
150
150
600
1150
Occupied transportation routes = M + N - 1
= 4 + 3 – 1
= 6
Index
Depot W - Customer A = +67 -51 +42 -43
= +15
Depot W - Customer B = +42 -51 +39 -24
= +6
Depot X - Customer A = +61 -39 +51 -67
= +6
Depot Y - Customer B = +47 -29 +67 -51 +39 -24
= +49
Depot Y - Customer B = +60 -51 +67 -29
= +47
Depot Z - Customer B = +31 -42 +39 -24
= +4
Total Transportation Cost = (250 X 51) + (150X 24) + (250 X 39) + (300 X 29) + (100 X 43) + (100 X 42)
= 12750 + 3600 + 2250 + 9750 + 8700 + 4300 + 4200
= RM43300
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
TUTORIAL – CHAPTER 8
Question 1
The Giant Farmer Company process cement, which it stocks in various warehouse. The market research study provided the following data:
Table 1 : Warehouse Table 2 : Demand
Warehouse Quantities (kg)
X 10000 A 12000
Y 16000 B 12000
Z 10000 C 12000
Table 3 : Shipping cost per kg (RM)
From / To I II III
X 10 6 12
Y 15 20 16
Z 8 18 22
Use the Northwest – Corner Approach Method to find the shipping that minimize shipping cost
Question 2
To
From
Sentosa
Sriwangi
Budi
C
Warehouse
Factory A
15
20
30
4000
Factory B
15
10
40
3500
Factory C
25
15
35
2500
Customer
Requirements
3500
3000
3500
10000
Use the Northwest – Corner Approach Method to find the shipping that minimize shipping cost
Answers
Question 1
To
From
I
II
III
Warehouse
X
10000 10
6
12
10000
Y
2000 15
12000 20
2000 16
16000
Z
8
18
10000 22
10000
Customer
Requirements
12000
12000
12000
26000
Total transportation cost = 10000(10) + 2000(15) + 12000(20) + 2000(16) + 10000(22)
= 10000 + 30000 + 240000 + 32000 + 220000
= RM622000
X – II : The index is +6 -20 +15 -15 = -9
X – III : The index is +12 -16 +15 -10 = +1
Z – I : The index is +8 -22 +16 -15 = -13
Z – II : The index is +18 -20 +16 -22 = -8
To
From
I
II
III
Warehouse
X
10000 10
6
12
10000
Y
15
12000 20
4000 16
16000
Z
2000 8
18
8000 22
10000
Customer
Requirements
12000
12000
12000
26000
Total transportation cost = 10000(10) + 12000(20) + 4000(16) + 2000 (8) + 8000(22)
= 10000 + 240000 + 64000 + 16000+ 176000
= RM622000
X – II : The index is +6 -20 +16 -22 +8 -10 = -22
X – III : The index is +12 -22 +8 -10 = -12
Y – I : The index is +15 -16 +22 -8 = +13
Z – I : The index is +18 -20 +16 -22 = -8
To
From
I
II
III
Warehouse
X
2000 10
8000 6
12
10000
Y
15
4000 20
12000 16
16000
Z
10000 8
18
22
10000
Customer
Requirements
12000
12000
12000
26000
Total transportation cost = 2000(10) + 8000(6) + 4000(20) + 12000 (16) + 10000(8)
= 2000 + 48000 + 80000 + 192000+ 80000
= RM420000
X – III : The index is +12 -16 +20 -6 = +10
Y – I : The index is +15 -20 +6 -10 = -9
Z – II : The index is +18 -6 +10 -8 = +14
Z – III : The index is +22 -16 +20 -6 +10 -8 = +22
To
From
I
II
III
Warehouse
X
10
10000 6
12
10000
Y
2000 15
2000 20
12000 16
16000
Z
10000 8
18
22
10000
Customer
Requirements
12000
12000
12000
26000
Total transportation cost = 10000(6) + 2000(15) + 2000(20) + 12000 (16) + 10000(8)
= 60000 + 30000 + 40000 + 192000+ 80000
= RM402000
X – I : The index is +10 -15 +20 -6 = +9
X – III : The index is +12 -16 +20 -6 = +10
Z – II : The index is +18 -6 +15 -8 = +5
Z – III : The index is +22 -16 +15 -8 = +13
Question 2
To
From
Sentosa
Sriwangi
Budi
C
Warehouse
Factory A
3500 15
500 20
30
4000
Factory B
15
2500 10
1000 40
3500
Factory C
25
15
2500 35
2500
Customer
Requirements
3500
3000
3500
10000
Total transportation cost = 3500(15) + 500(20) + 2500(10) + 1000(40) + 2500(35)
= 52500 + 10000 + 25000 + 40000 +87500
= RM215000
Factory A – Budi : The index is +30 -40 +10 -20 = -20
Factory B – Sentosa : The index is +15 -10 +20 -15 = +10
Factory C – Sentosa : The index is +25 -35 +40 -10 +20 -15 = +25
Factory C – Sriwangi : The index is +15 -35 +40 -10 = +10
To
From
Sentosa
Sriwangi
Budi
C
Warehouse
Factory A
2500 15
20
500 30
4000
Factory B
15
3000 10
500 40
3500
Factory C
25
15
2500 35
2500
Customer
Requirements
3500
3000
3500
10000
Total transportation cost = 2500(15) + 3000(10) + 500(30) + 500(40) + 2500(35)
= 52500 + 15000 + 30000 + 20000 + 87500
= RM205000
Factory A – Sriwangi : The index is +20 -10 +40 -30 = +20
Factory B – Sentosa : The index is +15 -40 +30 -15 = -10
Factory C – Sentosa : The index is +25 -35 +30 -15 = +25
Factory C – Sriwangi : The index is +15 -35 +40 -10 = +10
To
From
Sentosa
Sriwangi
Budi
C
Warehouse
Factory A
3000 15
20
1000 30
4000
Factory B
500 15
3000 10
40
3500
Factory C
25
15
2500 35
2500
Customer
Requirements
3500
3000
3500
10000
Total transportation cost = 3000(15) + 1000(30) + 500(15) + 3000(10) + 2500(35)
= 45000 + 30000 + 7500 + 30000 + 87500
= RM200000
Factory A – Sriwangi : The index is +20 -10 +15 -15 = +10
Factory B – Budi : The index is +25 -35 +30 -15 = +5
Factory C – Sentosa : The index is +15 -35 +30 -15 +15 -10 = 0
Factory C – Sriwangi : The index is +40 -30 +15 -15 = +10
Question
ABC Office Supplier has three depots located in various towns. It receives order for a total of 850 special filing cabinets from four customers.
Customer Order
A 300
B 200
C 200
In total the available filing cabinets in three depots are
Depot Available
X 250
Y 300
Z 300
The management wishes to minimize delivery costs by dispatching the filing cabinets from appropriate depot for each customer. The transportation costs from each depot to each customer per filing cabinet are given in Table 1.
Table 1 - Transportation Costs per Cabinet for ABC Office Supplier
To Requirements (customer)
From A B C
Depot X RM5 RM4 RM3
Depot Y 8 4 3
Depot Z 9 7 5
Use the Northwest – Corner Approach Method to find the shipping that minimize shipping cost
(25M)
To
From
Customer
A
Customer
B
Customer
C
Dummy
Depot
Available
Depot X
250 5
4
3
0
250
Depot Y
50 8
200 4
50 3
0
300
Depot Z
9
7
150 5
150 0
300
Customer
Requirements
300
200
200
150
850
Depot X – Customer A = +4 -4 +8 -5
= +3
Depot X – Customer C = +3 -3 +8 -5
= +3
Dummy = +0 -0 +5 -3 +8 -5
= +5
Dummy = +0 -0 +5 -3
= +2
Depot Z – Customer A = +9 -5 +3 -8
= -1
Depot Z – Customer B = +7 -5 +3 -4
= +1
Total transportation cost = 250(5) + 200(4) + 100(3) + 50(9) + 200(5) + 150(0)
= 1250 + 800 +300 +450 +1000 +0
=
To
From
Customer
A
Customer
B
Customer
C
Dummy
Depot
Available
Depot X
250 5
4
3
0
250
Depot Y
8
200 4
100 3
0
300
Depot Z
50 9
7
200 5
150 0
300
Customer
Requirements
300
200
200
150
850
Depot X – Customer B = +4 -4 +3 -5 +9 -5
= +2
Depot X – Customer C = +3 -5 +9 -3
= +4
Dummy = +0 -0 +9 -5
= +4
Depot Y – Customer A = +8 -3 +5 -9
= +1
Dummy = +0 -0 +5 -3
= +2
Depot Z – Customer B = +7 -5 +3 -4
= +1
Total transportation cost = 250(5) + 50(8) +200(4) + 50(3) +150(5) + 150(0)
= 1250 + 400 + 800 +150 +750 + 0
= RM33350
Question 1
The Giant Farmer Company process cement, which it stocks in various warehouse. The market research study provided the following data:
Table 1 : Warehouse
Warehouse Capacities (tones)
A 100
B 60
C 140
Table 2 : Demand
I 60
II 120
III 40
IV 80
Table 3 : Shipping cost per tones
I II III IV
A 30 36 38 26
B 40 28 32 34
C 50 24 38 44
Use the Northwest – Corner Approach Method to find the shipping that minimize shipping cost
(40M)
To
From
I
II
III
IV
Supply
A
60 30
40 36
38
26
100
B
40
60 28
32
34
60
C
50
20 24
40 38
80 44
140
Demand
60
120
40
80
300
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
A – III = +38 -38 +24 -36
= -12
A – IV = +26 -44 +24 -36
= -30
B – I = +40 -28 +36 -30
= +18
B – III = +32 -38 +24 -28
= -10
B – IV = +34 -44 +24 -28
= -14
C – I = +50 -24 +36 -30
= +32
Total Transportation Cost = (60 X 30) + (40X 36) + (60 X 28) + (20 X 24) + (40 X 38) + (80 X 44)
= 1800 + 1440 + 1680 + 480 + 1520 + 3520
= RM10440
To
From
I
II
III
IV
Supply
A
60 30
36
38
40 26
100
B
40
60 28
32
34
60
C
50
60 24
40 38
40 44
140
Demand
60
120
40
80
300
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
A – II = +36 -24 +44 -26
= +30
A – III = +38 -38 +44 -26
= +18
B – I = +40 -28 +24 -44 + 26 -30
= -12
B – III = +32 -38 +24 -28
= -10
B – IV = +34 -44 +24 -28
= -14
C – I = +50 -44 +26 -30
= +2
Total Transportation Cost = (60 X 30) + (60X 28) + (60 X 24) + (40 X 38) + (40 X 26) + (40 X 44)
= 1800 + 1680 + 1440 + 1520 + 1040 + 1360
= RM9240
To
From
I
II
III
IV
Supply
A
60 30
36
38
40 26
100
B
40
20 28
32
40 34
60
C
50
100 24
40 38
44
140
Demand
60
120
40
80
300
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
A – II = +36 -26 +34 -28
= +16
A – III = +38 -38 +24 -28 +34 -26
= +4
B – I = +40 -34 + 26 -30
= +2
B – III = +32 -38 +24 -28
= -10
C – I = +50 -24 +28 -34 +26 -30
= +16
C – IV = +44 -34 +28 -24
= +14
Total Transportation Cost = (60X30) + (20X28) + (100 X 24) + (40 X 38) + (40 X 26) + (40 X 34)
= 1800 + 560 + 2400 + 1520 + 1040 + 1360
= RM8680
To
From
I
II
III
IV
Supply
A
60 30
36
38
40 26
100
B
40
28
20 32
40 34
60
C
50
120 24
20 38
44
140
Demand
60
120
40
80
300
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
A – II = +36 -24 +38 -32 +34 -26
= +26
A – III = +38 -32 +34 -26
= +14
B – I = +40 -34 + 26 -30
= +2
B – III = +28 -24 +38 -32
= +10
C – I = +50 -38 +32 -34 +26 -30
= +6
C – IV = +44 -34 +32 -38
= +4
Total Transportation Cost = (60 X 30) + (120X24) + (20 X 32) + (20 X 38) + (40 X 26) + (40 X 34)
= 1800 + 2880 + 640 + 760 + 1040 + 1360
= RM8480
Least – Cost Solution
• This is a method that moves from an initial feasible solution to an optimal solution.
Transportation Table for ABC Office Supplier
To
From
Customer
A
Customer
B
Customer
C
Customer
D
Depot
Available
Depot X
13
2 11
15
20
2
Depot Y
1 17
1 14
4 12
13
6
Depot Z
2 18
18
15
5 12
7
Customer
Requirements
3
3
4
5
15
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
Depot X - Customer A = +13 -17 +14 -11
= -11
Depot X - Customer C = +15 -11 +14 -12
= +6
Depot X - Customer D = +20 -11 +14 -17 +18 -12
= +12
Depot Y - Customer D = +13 -17 +18 -12
= +2
Depot Z - Customer B = +18 -14 +17 -18
= +3
Depot Z - Customer C = +15 -12 +17 -18
= +2
Total Transportation Cost = (11 X 12) + (17 X 1) + (1 X 14) + (12 X 4) + (18 X 2) + (12 X 5)
= RM197
To
From
Customer
A
Customer
B
Customer
C
Customer
D
Depot
Available
Depot X
1 13
1 11
15
20
2
Depot Y
17
2 14
4 12
13
6
Depot Z
2 18
18
15
5 12
7
Customer
Requirements
3
3
4
5
15
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
Depot X - Customer A = +15 -12 +14 -11
= +6
Depot X - Customer C = +20 -12 +18 -13
= +13
Depot X - Customer D = +17 -14 +11 -13
= +1
Depot Y - Customer D = +18 -11 +13 -18
= +12
Depot Z - Customer B = +15 -12 +14 -11 +13 -18
= +1
Depot Z - Customer B = +15 -12 +17 -18
= +2
Total Transportation Cost = (1 X 13) + (11 X 1) + (2 X 14) + (12 X 4) + (18 X 2) + (12 X 5)
= RM196
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
TUTORIAL – CHAPTER 8
Question 1
The Giant Farmer Company process cement, which it stocks in various warehouse. The market research study provided the following data:
Table 1 : Warehouse Table 2 : Demand
Warehouse Quantities (kg)
X 10000 A 12000
Y 16000 B 12000
Z 10000 C 12000
Table 3 : Shipping cost per kg (RM)
From / To I II III
X 10 6 12
Y 15 20 16
Z 8 18 22
Use the Least – Cost Method to find the shipping that minimize shipping cost
Question 2
To
From
Sentosa
Sriwangi
Budi
C
Warehouse
Factory A
15
20
30
4000
Factory B
15
10
40
3500
Factory C
25
15
35
2500
Customer
Requirements
3500
3000
3500
10000
Use the Least – Cost Method to find the shipping that minimize shipping cost
Answers
Question 1
To
From
I
II
III
Warehouse
X
10
10000 6
12
10000
Y
2000 15
2000 20
12000 16
16000
Z
10000 8
18
22
10000
Customer
Requirements
12000
12000
12000
26000
Total transportation cost = 10000(6) + 2000(15) + 2000(20) + 12000 (16) + 10000(8)
= 60000 + 30000 + 40000 + 192000+ 80000
= RM402000
X – I : The index is +10 -15 +20 -6 = +9
X – III : The index is +12 -16 +20 -6 = +10
Z – II : The index is +18 -6 +15 -8 = +5
Z – III : The index is +22 -16 +15 -8 = +13
Question 2
To
From
Sentosa
Sriwangi
Budi
C
Warehouse
Factory A
2500 15
20
500 30
4000
Factory B
15
3000 10
500 40
3500
Factory C
25
15
2500 35
2500
Customer
Requirements
3500
3000
3500
10000
Total transportation cost = 2500(15) + 3000(10) + 500(30) + 500(40) + 2500(35)
= 52500 + 15000 + 30000 + 20000 + 87500
= RM205000
Factory A – Sriwangi : The index is +20 -10 +40 -30 = +20
Factory B – Sentosa : The index is +15 -40 +30 -15 = -10
Factory C – Sentosa : The index is +25 -35 +30 -15 = +25
Factory C – Sriwangi : The index is +15 -35 +40 -10 = +10
To
From
Sentosa
Sriwangi
Budi
C
Warehouse
Factory A
3000 15
20
1000 30
4000
Factory B
500 15
3000 10
40
3500
Factory C
25
15
2500 35
2500
Customer
Requirements
3500
3000
3500
10000
Total transportation cost = 3000(15) + 1000(30) + 500(15) + 3000(10) + 2500(35)
= 45000 + 30000 + 7500 + 30000 + 87500
= RM200000
Factory A – Sriwangi : The index is +20 -10 +15 -15 = +10
Factory B – Budi : The index is +25 -35 +30 -15 = +5
Factory C – Sentosa : The index is +15 -35 +30 -15 +15 -10 = 0
Factory C – Sriwangi : The index is +40 -30 +15 -15 = +10
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
EXERCISE – CHAPTER 8
Question
The Giant Farmer Company process cement, which it stocks in various warehouse. The market research study provided the following data:
Table 1 : Warehouse
Warehouse Capacities (tones)
W 250
X 400
Y 300
Z 200
Table 2 : Demand
A 400
B 150
C 600
Table 3 : Shipping cost per tones
From W to A : 67 From Y to A : 29
From W to B : 42 From Y to B : 47
From W to C : 51 From Y to C : 60
From X to A : 61 From Z to A : 43
From X to B : 24 From Z to B : 31
From X to C : 39 From Z to C : 42
Use the Least – Cost Method to find the shipping that minimize shipping cost
To
From
Customer
A
Customer
B
Customer
C
Warehouse
W
100 67
42
150 51
250
X
61
150 24
250 39
400
Y
300 29
47
60
300
Z
43
31
200 42
200
Customer
Requirements
150
150
600
1150
Occupied transportation routes = M + N - 1
= 4 + 3 – 1
= 6
Index
Depot W - Customer B = +42 -51 +39 -24
= +6
Depot X - Customer A = +61 -39 +51 -67
= +6
Depot Y - Customer B = +47 -24 +39 -51 +67 -29
= +49
Depot Y - Customer B = +60 -51 +67 -29
= +47
Depot Z - Customer A = +43 -42 +51 -67
= -15
Depot Z - Customer B = +31 -42 +39 -24
= +4
Total Transportation Cost = (100 X 67) + (150X 51) + (150 X 24) + (250 X 39) + (300 X 29) + (200 X 42)
= 6700 + 7650 + 3600 + 9750 + 8700 + 8400
= RM44800
To
From
Customer
A
Customer
B
Customer
C
Warehouse
W
67
42
250 51
250
X
61
150 24
250 39
400
Y
300 29
47
60
300
Z
100 43
31
100 42
200
Customer
Requirements
150
150
600
1150
Occupied transportation routes = M + N - 1
= 4 + 3 – 1
= 6
Index
Depot W - Customer A = +67 -51 +42 -43
= +15
Depot W - Customer B = +42 -51 +39 -24
= +6
Depot X - Customer A = +61 -39 +51 -67
= +6
Depot Y - Customer B = +47 -29 +67 -51 +39 -24
= +49
Depot Y - Customer B = +60 -51 +67 -29
= +47
Depot Z - Customer B = +31 -42 +39 -24
= +4
Total Transportation Cost = (250 X 51) + (150X 24) + (250 X 39) + (300 X 29) + (100 X 43) + (100 X 42)
= 12750 + 3600 + 2250 + 9750 + 8700 + 4300 + 4200
= RM43300
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
QUIZ – CHAPTER 8
Question 1
The Giant Farmer Company process cement, which it stocks in various warehouse. The market research study provided the following data:
Table 1 : Warehouse
Warehouse Capacities (tones)
A 300
B 150
C 250
Table 2 : Demand
I 350
II 125
III 100
IV 125
Table 3 : Shipping cost per tones
I II III IV
A 10 8 12 14
B 6 7 10 11
C 4 9 7 5
Use the Least – Cost Method to find the shipping that minimize shipping cost
(25M)
To
From
I
II
III
IV
Supply
A
175 10
125 8
12
14
300
B
150 6
7
10
11
150
C
25 4
9
100 7
125 5
250
Demand
350
125
100
125
700
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
A – III = +12 -7 +4 -10
= -1
A – IV = +14 -5 +4 -10
= +3
B – II = +7 -6 +10 -8
= +3
B – III = +10 -7 +4 -6
= +1
B – IV = +11 -5 +4 -6
= +4
C – II = +9 -8 +10 -4
= +7
Total Transportation Cost = 175 (10) + 150 (6) + 125 (8) + 25 (4) + 100 (7) + 125 (5)
= RM5075
To
From
I
II
III
IV
Supply
A
75 10
125 8
100 12
14
300
B
150 6
7
10
11
150
C
125 4
9
7
125 5
250
Demand
350
125
100
125
700
Occupied transportation routes = M + N - 1
= 3 + 4 – 1
= 6
A – IV = +14 -5 +4 -10
= +3
B – II = +7 -6 +10 -8
= +3
B – III = +10 -6 +10 –12
= +2
B – IV = +11 -5 +4 -6
= +4
C – II = +9 -8 +10 -4
= +7
C – III = +7 -12 +10 -4
= +1
Total Transportation Cost = 75 (10) + 100 (12) + 125 (8) + 150 (6) + 125 (4) + 125 (5)
= RM4975
Question
The Giant Farmer Company process cement, which it stocks in various warehouse. The market research study provided the following data:
Use the Northwest – Corner Approach Method to find the shipping that minimize shipping cost
To
From
A
B
C
Factory
W
4
3
3
35
Y
6
7
6
50
Z
8
2
5
50
Demand
30
65
40
135
(25m)
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
QUIZ – CHAPTER 8 (ANSWERS)
CLASS : DRM3
To
From
A
B
C
Factory
W
30 / 4
5 / 3
3
35
Y
6
50 / 7
6
50
Z
8
10 / 2
40 / 5
50
Demand
30
65
40
135
Each / ========= 1m
Indeks
W – C = +3 -5 +2 -3
= -3 (0.5m)
Y – A = +6 -7 +3 -4
= -2 (0.5m)
Y – C = +6 -7 +2 -5
= -4 (0.5m)
Z – A = +8 -2 +3 -4
= +5 (0.5m)
Total transportation cost = (30 X4) + (3X5) + (50X7) + (10X2) + (40X5) (1m)
= RM705 (1m)
To
From
A
B
C
Kilang
W
30 / 4
5 / 3
3
35
Y
6
10 / 7
40 / 6
50
Z
8
50 / 2
5
50
Permintaan
30
65
40
135
Each / ========= 1m
Indeks
W – C = +3 -3 +7 -6
= +1 (0.5m)
Y – A = +6 -7 +3 -4
= -2 (0.5m)
Z – A = +8 -2 +3 -4
= +5 (0.5m)
Z – C = +5 -6 +7 -2
= +4 (0.5m)
Total transportation cost = (30 X4) + (3X5) + (10X7) + (50X2) + (40X6) (1m)
= RM545 (1m)
To
From
A
B
C
Factory
W
20 / 4
15 / 3
3
35
Y
10 / 6
7
40 / 6
50
Z
8
50 / 2
5
50
Demand
30
65
40
135
Each / ========= 1m
Indeks
W – C = +3 -4 +6 -6
= -1 (0.5m)
Y – B = +7 -3 +6 -4
= +6 (0.5m)
Z – A = +8 -2 +3 -4
= +5 (0.5m)
Z – C = +5 -6 +6 -4 +3 -2
= +2 (0.5m)
Total transportation cost = (20 X4) + (15X3) + (10X6) + (50X2) + (40X6)(1m)
= RM525 (1m)
To
From
A
B
C
Factory
W
4
15 / 3
20 / 3
35
Y
30 / 6
7
20 / 6
50
Z
8
50 / 2
5
50
Demand
30
65
40
135
Each / ========= 1m
Indeks
W – A = +4 -6 +6 -3
= +1 (0.5m)
Y – B = +7 -6 +3 -3
= +1 (0.5m)
Z – A = +8 -2 +3 -3 +6 -6
= +6 (0.5m)
Z – C = +5 -3 +3 -2
= +3 (0.5m)
Total transportation cost = (30 X6) + (15X3) + (50X2) + (20X3) + (20X6)(1m)
= RM505 (1m)
Friday, February 5, 2010
chapter 8 assignment method
CHAPTER 8
ASSIGNMENT METHOD
• Involves assigning tasks or jobs resources.
• Eg: assigning jobs to machines, contracts to bidders, people to projects and salespeople to territories
• Objective – minimize total costs or time required to perform the tasks.
• One important characteristics of assignment problem is that only one job (or worker) to one machine (or project).
• Assignment method is a special form of transportation problem in which there is only one item at each of the various sources and only one item is required at each of the various destinations.
• Each assignment problem is usually arranged in either a table or a matrix.
• Generally, the rows contain the objects, people or sources to assign and column contain the tasks or destinations on things to assign on.
• Assignment service engineers to requests so as that the total costs are minimized.
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
Step 4
a. Find the smallest number NOT covered by a line, called X.
b. Subtract X from every the uncovered number in the table.
c. Add X to every number lying at the intersection of horizontal and vertical lines.
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
EXERCISES – CHAPTER 8
Question 1
The operations manager of King Manufacturing must assign 3 tasks to 3 machines. Cost data are presented below.
A B C
C1
11 12 17
C2
7 11 20
C3
5 8 16
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 11 (row 1), 7 (row 2) and 5 (row 3).
A B C
C1
0 1 6
C2
0 4 13
C3
0 2 11
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 1 (column 2) and 6 (column 3).
A B C
C1
0 0 0
C2
0 3 7
C3
0 1 5
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
A B C
C1
0
0 0
C2
0 3 7
C3
0 1 5
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
(3 – 1 = 2), (7 - 1 = 6), (1 – 1 = 0) and (5 – 1 = 4)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(0 + 1 = 1)
A B C
C1
0 0 0
C2
0 3 7
C3
0 1 5
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
A B C
C1
3 0 [0]
C2
[0] 1 5
C3
0 [0] 3
Total assignment method
C1 - C = 17
C2 - A = 7
C3 - B = 8
32
Question 2
The operations manager of King Manufacturing must assign 4 tasks to 4 machines. Cost data are presented below.
Kangar Tampin Alor Gajah Mersing
Irdina
40 50 44 56
Nadiatul
30 36 46 34
Nurin
38 34 42 48
Nomie
50 46 48 48
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 40 (row 1), 30 (row 2), 34 (row 3) and 46 (row 4).
Kangar Tampin Alor Gajah Mersing
Irdina
0 10 4 16
Nadiatul
0 6 16 4
Nurin
4 0 8 14
Nomie
4 0 2 2
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 0 (column 2), 2 (column 3) and 2 (column 4).
Kangar Tampin Alor Gajah Mersing
Irdina
0 10 2 14
Nadiatul
0 6 14 2
Nurin
4 0 6 12
Nomie
4 0 0 0
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
Kangar Tampin Alor Gajah Mersing
Irdina
0
10 2 14
Nadiatul
0 6 14 2
Nurin
4
0 6 12
Nomie
4
0 0 0
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 2.
b. Subtract X from every the uncovered number in the table.
(10 – 2 = 8), (2 – 2 = 0), (14 – 2 = 20), (6 – 2 = 4), (14 – 2 = 12) and (2 – 2 = 0)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(4 + 2 = 6) and (4 + 2 = 6)
Kangar Tampin Alor Gajah Mersing
Irdina
0
10 2 14
Nadiatul
0 6 14 2
Nurin
4
0 6 12
Nomie
4
0 0 0
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
Kangar Tampin Alor Gajah Mersing
Irdina
[0] 8 0 12
Nadiatul
0 4 12 [0]
Nurin
6 [0] 6 12
Nomie
6 0 [0] 0
Total assignment method
Irdina - Kangar = 40
Nadiatul - Mersing = 34
Nurin - Tampin = 34
Nomie - Alor Gajah = 48
156
Question 3
The operations manager of King Manufacturing must assign 4 tasks to 4 machines. Cost data are presented below.
Kangar Tampin Alor Gajah Mersing
Irdina
25 18 23 14
Nadiatul
38 15 53 23
Nurin
15 17 41 30
Nomie
26 28 36 29
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 14 (row 1), 15 (row 2), 15 (row 3) and 26 (row 4).
Kangar Tampin Alor Gajah Mersing
Irdina
11 4 9 0
Nadiatul
23 0 38 8
Nurin
0 2 26 15
Nomie
0 2 10 3
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 0 (column 2), 9 (column 3) and 0 (column 4).
Kangar Tampin Alor Gajah Mersing
Irdina
11 4 0 0
Nadiatul
23 0 29 8
Nurin
0 2 17 15
Nomie
0 2 1 3
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
Kangar Tampin Alor Gajah Mersing
Irdina
11
4 0 0
Nadiatul
23
0 29 8
Nurin
0 2 17 15
Nomie
0 2 1 3
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 2.
b. Subtract X from every the uncovered number in the table.
(10 – 2 = 8), (2 – 2 = 0), (14 – 2 = 20), (6 – 2 = 4), (14 – 2 = 12) and (2 – 2 = 0)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(4 + 2 = 6) and (4 + 2 = 6)
Kangar Tampin Alor Gajah Mersing
Irdina
12 4 0 0
Nadiatul
24 0 29 8
Nurin
0 1 16 14
Nomie
0 1 0 2
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
Kangar Tampin Alor Gajah Mersing
Irdina
12 4 0 [0]
Nadiatul
24 [0] 29 8
Nurin
[0] 1 16 14
Nomie
0 1 [0] 2
Total assignment method
Irdina - Kangar = 14
Nadiatul - Mersing = 15
Nurin - Tampin = 15
Nomie - Alor Gajah = 36
80
Question 4
The operations manager of King Manufacturing must assign 4 tasks to 4 machines. Cost data are presented below.
A B C D
Z1
5 3 1 5
Z2
6 6 2 7
Z3
5 5 3 8
Z4
8 2 4 3
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 1 (row 1), 2 (row 2), 3 (row 3) and 3 (row 4).
A B C D
Z1
4 2 0 4
Z2
4 4 0 5
Z3
2 2 0 5
Z4
6 0 2 1
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 2 (column 1), 0 (column 2), 0 (column 3) and 1 (column 4).
A B C D
Z1
2 2 0 3
Z2
2 4 0 4
Z3
0 2 0 4
Z4
4 0 2 0
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
A B C D
Z1
2
2 0
3
Z2
2 4 0 4
Z3
0
2 0 4
Z4
4
0 2 0
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 2.
b. Subtract X from every the uncovered number in the table.
(2 – 2 = 0), (2 – 2 = 0), (3 – 2 = 1), (2 – 0 = 2) and (4 – 2 = 2)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(0 + 2 = 2) and (2 + 2 = 4)
A B C D
Z1
0 0 0 1
Z2
0 2 0 2
Z3
0 2 2 4
Z4
4 0 4 0
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
A B C D
Z1
0 [0] 0 1
Z2
0 2 [0] 2
Z3
[0] 2 2 4
Z4
4 0 4 [0]
Total assignment method
Z1 - B = 3
Z2 - C = 2
Z3 - A = 5
Z4 - D = 3
13
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
ASSIGNMENT – CHAPTER 8
Question 1
The operations manager of King Manufacturing must assign 5 tasks to 5 machines. Cost data are presented below.
I II III IV V
A
3 5 4 8 2
B
9 4 3 6 2
C
11 6 8 10 9
D
6 10 4 12 5
E
3 5 6 4 9
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 2 (row 1), 2 (row 2), 6 (row 3), 4 (row 4) and 3 (row 5)
I II III IV V
A
1 3 2 6 0
B
7 2 1 4 0
C
5 0 2 4 3
D
2 6 0 8 1
E
0 2 3 1 6
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 0 (column 2), 0 (column 3), 1 (column 4) and 0 (column 5)
I II III IV V
A
1 3 2 5 0
B
7 2 1 3 0
C
5 0 2 3 3
D
2 6 0 7 1
E
0 2 3 0 6
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
I II III IV V
A
1 3 2 5 0
B
7 2 1 3 0
C
5
0 2 3 3
D
2
6 0 7 1
E
0
2 3 0 6
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
(1 – 1 = 0), (3 - 1 = 2), (2 – 1 = 1), (5 – 1 = 4), (7 – 1 = 6), (2 -1 = 1), (1 – 1 = 0) and (3 – 1 = 2)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(3 + 1 = 4), (1 + 1 = 2) and (6 + 1 = 7)
I II III IV V
A
0 2 1 4 0
B
6 1 0 2 0
C
5 0 2 3 4
D
2 6 0 7 2
E
0 2 3 0 7
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
I II III IV V
A
[0] 2 1 4 0
B
6 1 0 2 [0]
C
5 [0] 2 3 4
D
2 6 [0] 7 2
E
0 2 3 [0] 7
Total assignment method
A - I = 3
B - V = 2
C - II = 6
D - III = 4
E - IV = 4
19
Question 2
The operations manager of King Manufacturing must assign 6 tasks to 6 machines. Cost data are presented below.
I II III IV V VI
A
60 22 34 42 30 60
B
22 52 16 32 18 48
C
29 16 58 28 22 55
D
42 32 28 46 15 30
E
30 18 25 15 45 42
F
50 48 27 30 44 60
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 22 (row 1), 16 (row 2), 16 (row 3), 15 (row 4), 15 (ROW 5) and 27 (row 65)
I II III IV V VI
A
38 0 12 20 8 38
B
6 36 0 16 2 32
C
13 0 42 12 6 39
D
27 17 13 31 0 15
E
15 3 10 0 30 27
F
23 21 0 3 17 33
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 6 (column 1), 0 (column 2), 0 (column 3), (column 4), 0 (column 5) and 15 (column 6)
I II III IV V VI
A
32 0 12 20 8 23
B
0 36 0 16 2 17
C
7 0 42 12 6 14
D
21 17 13 31 0 0
E
9 3 10 0 30 12
F
17 21 0 3 17 18
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
I II III IV V VI
A
32 0 12 20 8 23
B
0 36 0 16 2 17
C
7 0 42 12 6 14
D
21
17 13 31 0 0
E
9 3 10 0 30 12
F
17 21
0 3 17
8
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
(32 - 6 = 26), (12 - 6 = 6), (20 – 6 = 14), (8 – 6 = 2), (23 – 6 = 17), (7 - 6 = 1), (42 – 6 = 36), (12 – 6 = 6), (6 – 6 = 0) and (14 – 6 = 8)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(36 + 6 = 42), (17 + 6 = 23), (3 + 6 = 9) and (21 + 6 = 27)
I II III IV V VI
A
32 0 12 20 8 23
B
0 36 0 16 2 17
C
7 0 42 12 6 14
D
21 17 13 31 0 0
E
9 3 10 0 30 12
F
17 21 0 3 17 18
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
I II III IV V VI
A
26 0 6 14 2 17
B
0 42 0 16 2 17
C
1 0 36 6 0 8
D
21 23 13 31 0 0
E
9 9 10 0 30 12
F
17 27 0 3 17 8
Total assignment method
A - II = 22
B - I = 22
C - V = 22
D - VI = 30
E - IV = 15
F - III = 27
138
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
QUIZ – CHAPTER 8
Question 1
The operations manager of King Manufacturing must assign 3 tasks to 3 machines. Cost data are presented below.
1 2 3
C3
800 1100 1200
C5
500 1600 1300
C8
500 1000 2300
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 800 (row 1), 500 (row 2) and 500 (row 3).
1 2 3
C3
0 300 400
C5
0 1100 800
C8
0 500 1800
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 300 (column 2) and 400 (column 3).
1 2 3
C3
0 0 0
C5
0 800 400
C8
0 200 1400
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
1 2 3
C3
0
0 0
C5
0 800 400
C8
0 200 1400
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
(800 – 200 = 600), (400 - 200 = 200), (200 – 200 = 0) and (1400 – 200 = 1200)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(0 + 1 = 1)
1 2 3
C3
0 0 0
C5
0 600 200
C8
0 0 1200
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
1 2 3
C3
0 0 [0]
C5
[0] 600 200
C8
0 [0] 1200
Total assignment method
C8 - 2 = 1200
C5 - 1 = 500
C3 - 3 = 1200
2700
Question 1
The operations manager of King Manufacturing must assign 5 tasks to 5 machines. Cost data are presented below.
I II III IV V
A
20 25 15 10 12
B
18 20 20 16 15
C
18 19 16 18 12
D
20 22 18 15 10
E
18 20 15 16 10
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 10 (row 1), 15 (row 2), 12 (row 3), 10 (row 4) and 10 (row 5)
I II III IV V
A
10 15 5 0 2
B
3 5 5 1 0
C
6 7 4 6 0
D
10 12 8 5 0
E
8 10 5 6 0
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 3 (column 1), 5 (column 2), 4 (column 3), 0 (column 4) and 0 (column 5)
I II III IV V
A
7 10 1 0 2
B
0 0 1 1 0
C
3 2 0 6 0
D
7 7 4 5 0
E
5 5 1 6 0
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
I II III IV V
A
7
10 1 0 2
B
0
0 1 1 0
C
3
2 0 6 0
D
7 7 4 5 0
E
5 5 1 6 0
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
c. Add X to every number lying at the intersection of horizontal and vertical lines.
I II III IV V
A
7 10 1 0 3
B
0 0 1 1 1
C
3 2 0 6 1
D
6 6 3 4 0
E
4 4 0 5 0
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row. [0]
c. Assignments which is NOT in a) or b)
I II III IV V
A
7
10 1
[0] 3
B
0
[0] 1 1 1
C
3 2 0 6 1
D
6 6 3 4 [0]
E
4 4 [0] 5 0
I II III IV V
A
7 10 3 [0] 5
B
[0] 0 3 2 3
C
1 [0] 0 4 1
D
4 4 3 2 [0]
E
2 2 [0] 3 0
Total assignment method
A - IV = 10
B - I = 18
C - II = 19
D - V = 10
E - III = 15
72
ASSIGNMENT METHOD
• Involves assigning tasks or jobs resources.
• Eg: assigning jobs to machines, contracts to bidders, people to projects and salespeople to territories
• Objective – minimize total costs or time required to perform the tasks.
• One important characteristics of assignment problem is that only one job (or worker) to one machine (or project).
• Assignment method is a special form of transportation problem in which there is only one item at each of the various sources and only one item is required at each of the various destinations.
• Each assignment problem is usually arranged in either a table or a matrix.
• Generally, the rows contain the objects, people or sources to assign and column contain the tasks or destinations on things to assign on.
• Assignment service engineers to requests so as that the total costs are minimized.
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
Step 4
a. Find the smallest number NOT covered by a line, called X.
b. Subtract X from every the uncovered number in the table.
c. Add X to every number lying at the intersection of horizontal and vertical lines.
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
EXERCISES – CHAPTER 8
Question 1
The operations manager of King Manufacturing must assign 3 tasks to 3 machines. Cost data are presented below.
A B C
C1
11 12 17
C2
7 11 20
C3
5 8 16
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 11 (row 1), 7 (row 2) and 5 (row 3).
A B C
C1
0 1 6
C2
0 4 13
C3
0 2 11
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 1 (column 2) and 6 (column 3).
A B C
C1
0 0 0
C2
0 3 7
C3
0 1 5
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
A B C
C1
0
0 0
C2
0 3 7
C3
0 1 5
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
(3 – 1 = 2), (7 - 1 = 6), (1 – 1 = 0) and (5 – 1 = 4)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(0 + 1 = 1)
A B C
C1
0 0 0
C2
0 3 7
C3
0 1 5
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
A B C
C1
3 0 [0]
C2
[0] 1 5
C3
0 [0] 3
Total assignment method
C1 - C = 17
C2 - A = 7
C3 - B = 8
32
Question 2
The operations manager of King Manufacturing must assign 4 tasks to 4 machines. Cost data are presented below.
Kangar Tampin Alor Gajah Mersing
Irdina
40 50 44 56
Nadiatul
30 36 46 34
Nurin
38 34 42 48
Nomie
50 46 48 48
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 40 (row 1), 30 (row 2), 34 (row 3) and 46 (row 4).
Kangar Tampin Alor Gajah Mersing
Irdina
0 10 4 16
Nadiatul
0 6 16 4
Nurin
4 0 8 14
Nomie
4 0 2 2
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 0 (column 2), 2 (column 3) and 2 (column 4).
Kangar Tampin Alor Gajah Mersing
Irdina
0 10 2 14
Nadiatul
0 6 14 2
Nurin
4 0 6 12
Nomie
4 0 0 0
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
Kangar Tampin Alor Gajah Mersing
Irdina
0
10 2 14
Nadiatul
0 6 14 2
Nurin
4
0 6 12
Nomie
4
0 0 0
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 2.
b. Subtract X from every the uncovered number in the table.
(10 – 2 = 8), (2 – 2 = 0), (14 – 2 = 20), (6 – 2 = 4), (14 – 2 = 12) and (2 – 2 = 0)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(4 + 2 = 6) and (4 + 2 = 6)
Kangar Tampin Alor Gajah Mersing
Irdina
0
10 2 14
Nadiatul
0 6 14 2
Nurin
4
0 6 12
Nomie
4
0 0 0
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
Kangar Tampin Alor Gajah Mersing
Irdina
[0] 8 0 12
Nadiatul
0 4 12 [0]
Nurin
6 [0] 6 12
Nomie
6 0 [0] 0
Total assignment method
Irdina - Kangar = 40
Nadiatul - Mersing = 34
Nurin - Tampin = 34
Nomie - Alor Gajah = 48
156
Question 3
The operations manager of King Manufacturing must assign 4 tasks to 4 machines. Cost data are presented below.
Kangar Tampin Alor Gajah Mersing
Irdina
25 18 23 14
Nadiatul
38 15 53 23
Nurin
15 17 41 30
Nomie
26 28 36 29
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 14 (row 1), 15 (row 2), 15 (row 3) and 26 (row 4).
Kangar Tampin Alor Gajah Mersing
Irdina
11 4 9 0
Nadiatul
23 0 38 8
Nurin
0 2 26 15
Nomie
0 2 10 3
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 0 (column 2), 9 (column 3) and 0 (column 4).
Kangar Tampin Alor Gajah Mersing
Irdina
11 4 0 0
Nadiatul
23 0 29 8
Nurin
0 2 17 15
Nomie
0 2 1 3
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
Kangar Tampin Alor Gajah Mersing
Irdina
11
4 0 0
Nadiatul
23
0 29 8
Nurin
0 2 17 15
Nomie
0 2 1 3
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 2.
b. Subtract X from every the uncovered number in the table.
(10 – 2 = 8), (2 – 2 = 0), (14 – 2 = 20), (6 – 2 = 4), (14 – 2 = 12) and (2 – 2 = 0)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(4 + 2 = 6) and (4 + 2 = 6)
Kangar Tampin Alor Gajah Mersing
Irdina
12 4 0 0
Nadiatul
24 0 29 8
Nurin
0 1 16 14
Nomie
0 1 0 2
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
Kangar Tampin Alor Gajah Mersing
Irdina
12 4 0 [0]
Nadiatul
24 [0] 29 8
Nurin
[0] 1 16 14
Nomie
0 1 [0] 2
Total assignment method
Irdina - Kangar = 14
Nadiatul - Mersing = 15
Nurin - Tampin = 15
Nomie - Alor Gajah = 36
80
Question 4
The operations manager of King Manufacturing must assign 4 tasks to 4 machines. Cost data are presented below.
A B C D
Z1
5 3 1 5
Z2
6 6 2 7
Z3
5 5 3 8
Z4
8 2 4 3
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 1 (row 1), 2 (row 2), 3 (row 3) and 3 (row 4).
A B C D
Z1
4 2 0 4
Z2
4 4 0 5
Z3
2 2 0 5
Z4
6 0 2 1
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 2 (column 1), 0 (column 2), 0 (column 3) and 1 (column 4).
A B C D
Z1
2 2 0 3
Z2
2 4 0 4
Z3
0 2 0 4
Z4
4 0 2 0
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
A B C D
Z1
2
2 0
3
Z2
2 4 0 4
Z3
0
2 0 4
Z4
4
0 2 0
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 2.
b. Subtract X from every the uncovered number in the table.
(2 – 2 = 0), (2 – 2 = 0), (3 – 2 = 1), (2 – 0 = 2) and (4 – 2 = 2)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(0 + 2 = 2) and (2 + 2 = 4)
A B C D
Z1
0 0 0 1
Z2
0 2 0 2
Z3
0 2 2 4
Z4
4 0 4 0
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
A B C D
Z1
0 [0] 0 1
Z2
0 2 [0] 2
Z3
[0] 2 2 4
Z4
4 0 4 [0]
Total assignment method
Z1 - B = 3
Z2 - C = 2
Z3 - A = 5
Z4 - D = 3
13
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
ASSIGNMENT – CHAPTER 8
Question 1
The operations manager of King Manufacturing must assign 5 tasks to 5 machines. Cost data are presented below.
I II III IV V
A
3 5 4 8 2
B
9 4 3 6 2
C
11 6 8 10 9
D
6 10 4 12 5
E
3 5 6 4 9
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 2 (row 1), 2 (row 2), 6 (row 3), 4 (row 4) and 3 (row 5)
I II III IV V
A
1 3 2 6 0
B
7 2 1 4 0
C
5 0 2 4 3
D
2 6 0 8 1
E
0 2 3 1 6
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 0 (column 2), 0 (column 3), 1 (column 4) and 0 (column 5)
I II III IV V
A
1 3 2 5 0
B
7 2 1 3 0
C
5 0 2 3 3
D
2 6 0 7 1
E
0 2 3 0 6
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
I II III IV V
A
1 3 2 5 0
B
7 2 1 3 0
C
5
0 2 3 3
D
2
6 0 7 1
E
0
2 3 0 6
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
(1 – 1 = 0), (3 - 1 = 2), (2 – 1 = 1), (5 – 1 = 4), (7 – 1 = 6), (2 -1 = 1), (1 – 1 = 0) and (3 – 1 = 2)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(3 + 1 = 4), (1 + 1 = 2) and (6 + 1 = 7)
I II III IV V
A
0 2 1 4 0
B
6 1 0 2 0
C
5 0 2 3 4
D
2 6 0 7 2
E
0 2 3 0 7
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
I II III IV V
A
[0] 2 1 4 0
B
6 1 0 2 [0]
C
5 [0] 2 3 4
D
2 6 [0] 7 2
E
0 2 3 [0] 7
Total assignment method
A - I = 3
B - V = 2
C - II = 6
D - III = 4
E - IV = 4
19
Question 2
The operations manager of King Manufacturing must assign 6 tasks to 6 machines. Cost data are presented below.
I II III IV V VI
A
60 22 34 42 30 60
B
22 52 16 32 18 48
C
29 16 58 28 22 55
D
42 32 28 46 15 30
E
30 18 25 15 45 42
F
50 48 27 30 44 60
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 22 (row 1), 16 (row 2), 16 (row 3), 15 (row 4), 15 (ROW 5) and 27 (row 65)
I II III IV V VI
A
38 0 12 20 8 38
B
6 36 0 16 2 32
C
13 0 42 12 6 39
D
27 17 13 31 0 15
E
15 3 10 0 30 27
F
23 21 0 3 17 33
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 6 (column 1), 0 (column 2), 0 (column 3), (column 4), 0 (column 5) and 15 (column 6)
I II III IV V VI
A
32 0 12 20 8 23
B
0 36 0 16 2 17
C
7 0 42 12 6 14
D
21 17 13 31 0 0
E
9 3 10 0 30 12
F
17 21 0 3 17 18
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
I II III IV V VI
A
32 0 12 20 8 23
B
0 36 0 16 2 17
C
7 0 42 12 6 14
D
21
17 13 31 0 0
E
9 3 10 0 30 12
F
17 21
0 3 17
8
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
(32 - 6 = 26), (12 - 6 = 6), (20 – 6 = 14), (8 – 6 = 2), (23 – 6 = 17), (7 - 6 = 1), (42 – 6 = 36), (12 – 6 = 6), (6 – 6 = 0) and (14 – 6 = 8)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(36 + 6 = 42), (17 + 6 = 23), (3 + 6 = 9) and (21 + 6 = 27)
I II III IV V VI
A
32 0 12 20 8 23
B
0 36 0 16 2 17
C
7 0 42 12 6 14
D
21 17 13 31 0 0
E
9 3 10 0 30 12
F
17 21 0 3 17 18
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
I II III IV V VI
A
26 0 6 14 2 17
B
0 42 0 16 2 17
C
1 0 36 6 0 8
D
21 23 13 31 0 0
E
9 9 10 0 30 12
F
17 27 0 3 17 8
Total assignment method
A - II = 22
B - I = 22
C - V = 22
D - VI = 30
E - IV = 15
F - III = 27
138
UNGKU OMAR POLYTECHNICS
P3724 – MATHEMATICS FOR RETAILING
QUIZ – CHAPTER 8
Question 1
The operations manager of King Manufacturing must assign 3 tasks to 3 machines. Cost data are presented below.
1 2 3
C3
800 1100 1200
C5
500 1600 1300
C8
500 1000 2300
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 800 (row 1), 500 (row 2) and 500 (row 3).
1 2 3
C3
0 300 400
C5
0 1100 800
C8
0 500 1800
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 0 (column 1), 300 (column 2) and 400 (column 3).
1 2 3
C3
0 0 0
C5
0 800 400
C8
0 200 1400
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
1 2 3
C3
0
0 0
C5
0 800 400
C8
0 200 1400
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
(800 – 200 = 600), (400 - 200 = 200), (200 – 200 = 0) and (1400 – 200 = 1200)
c. Add X to every number lying at the intersection of horizontal and vertical lines.
(0 + 1 = 1)
1 2 3
C3
0 0 0
C5
0 600 200
C8
0 0 1200
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row.
c. Assignments which is NOT in a) or b)
1 2 3
C3
0 0 [0]
C5
[0] 600 200
C8
0 [0] 1200
Total assignment method
C8 - 2 = 1200
C5 - 1 = 500
C3 - 3 = 1200
2700
Question 1
The operations manager of King Manufacturing must assign 5 tasks to 5 machines. Cost data are presented below.
I II III IV V
A
20 25 15 10 12
B
18 20 20 16 15
C
18 19 16 18 12
D
20 22 18 15 10
E
18 20 15 16 10
Use the assignment algorithm to solve this problem.
Answer
Step 1
Reduce each row by the SMALLEST number in the row. Subtract these values from each element in the row produces.
The smallest numbers are 10 (row 1), 15 (row 2), 12 (row 3), 10 (row 4) and 10 (row 5)
I II III IV V
A
10 15 5 0 2
B
3 5 5 1 0
C
6 7 4 6 0
D
10 12 8 5 0
E
8 10 5 6 0
Step 2
Reduce each column by the SMALLEST number in the column. Deduct each smallest number from every number in that column.
The smallest numbers are 3 (column 1), 5 (column 2), 4 (column 3), 0 (column 4) and 0 (column 5)
I II III IV V
A
7 10 1 0 2
B
0 0 1 1 0
C
3 2 0 6 0
D
7 7 4 5 0
E
5 5 1 6 0
Step 3
Draw the MINIMUM possible number of lines to cover all zeros. The lines may be horizontal or vertical.
I II III IV V
A
7
10 1 0 2
B
0
0 1 1 0
C
3
2 0 6 0
D
7 7 4 5 0
E
5 5 1 6 0
Step 4
a. Find the smallest number NOT covered by a line, called X. The smallest number is 1.
b. Subtract X from every the uncovered number in the table.
c. Add X to every number lying at the intersection of horizontal and vertical lines.
I II III IV V
A
7 10 1 0 3
B
0 0 1 1 1
C
3 2 0 6 1
D
6 6 3 4 0
E
4 4 0 5 0
Step 5
When the optimal assignment is found, the actual assignments can be made by assigning to:
a. any zero which is unique to BOTH a column and a row.
b. Any zero which is unique to column OR a row. [0]
c. Assignments which is NOT in a) or b)
I II III IV V
A
7
10 1
[0] 3
B
0
[0] 1 1 1
C
3 2 0 6 1
D
6 6 3 4 [0]
E
4 4 [0] 5 0
I II III IV V
A
7 10 3 [0] 5
B
[0] 0 3 2 3
C
1 [0] 0 4 1
D
4 4 3 2 [0]
E
2 2 [0] 3 0
Total assignment method
A - IV = 10
B - I = 18
C - II = 19
D - V = 10
E - III = 15
72
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