Problems:
Transportation Problem Set
1. Consider a transportation problem with 4 sources and 3 demand points.
(a) Write the min-cost model in full (without using ∑ notation).
(b) Draw the network.
(c) Construct the standard data table.
2. Consider a transportation problem for which cij = hi + hj , where is a handling cost at node i. (This can be unloading/loading charge from/to a barge or railroad car.) Prove that if total supply equals total demand, every feasible shipping policy is optimal.
3. Prove or give a counter-example to each of the following.
(a) If assignment costs are unique, the optimal assignment is unique.
(b) If there is excess supply and all shipping costs are positive, every optimal shipping policy ships only the amount of total demand (i.e., no demand is over-satisfied).
4. A 400-meter relay requires 4 different swimmers who each swim 100 meters of backstroke, breaststroke, butterfly, and freestyle. A coach has 5 swimmers whose expected times (in seconds) are given in the following table.
|
backstroke
|
breaststroke
|
butterfly
|
freestyle
|
Chris
|
65
|
73
|
63
|
57
|
Charlie
|
67
|
70
|
65
|
58
|
Francis
|
68
|
72
|
69
|
55
|
Jackie
|
67
|
75
|
70
|
59
|
Terry
|
71
|
69
|
75
|
57
|
(a) How should the coach assign swimmers to the relay so as to minimize their total time?
(b) Consider the swimmer not assignment to any event. How much must each of the 4 event-times decrease for that swimmer to be assigned to an event? Who is replaced?
(c) How valuable would a new swimmer be with the following times:
|
backstroke
|
breaststroke
|
butterfly
|
freestyle
|
No Name
|
66
|
72
|
68
|
57
|
Attachment:- Transportation Problem Set Templates.rar