6. Two godowns A and B have grain capacity of 100 quintals and 50 quintals respectively. They supply to 3 ration shops, D, E and F whose requirements are 60, 50 and 40 quintals respectively. The cost of transportation per quintal from the godowns to the shops is given in the following table:
Transportation cost per quintal (in Rs) | ||
From/To | A | B |
D | 6 | 4 |
E | 3 | 2 |
F | 2.50 | 3 |
How should the supplies be transported in order that the transportation cost is minimal? What is the minimum cost?
Let godown A supply x and y quintals of grain to shops D and E respectively. Then, (100-x-y) will be supplied to shop F. Requirements at shop D is 60 since godown A supplies x . Therefore, the remaining (60-x) quintals of grain will be transported from godown B.
Similarly, (50-y) quintals and 40-(100-x-y)=(x+y-60) will be transported from godown B to shop E and F respectively. The problem can be represented diagrammatically as follows:
and
and
Total transportation cost z is given by,
The mathematical formulation of the given problem is as follows:
Minimize :
Subject to constraint,
The feasible region determined by constraints is as follows:
The corner points of the feasible region are
The value of Z at corner points is as shown :
corner points | ||
560 | ||
620 | ||
610 | ||
510 | minimum |
Therefore, 510 may or may not be the minimum value of Z.
Hence, Z has a minimum value of 510 at point