Exercise 1: Transportation Problem {Supply = Demand} An oil supply company has four depots in Victoria each with different supply capabilities. The four depots are required to service the needs of four outlets that have different demands. The available supplies at the depots, the demands of the outlets and the cost of delivery are given in the following table: i _ _ Outlet ' Supply i Depot X1 : X2 X3 X4 E i D1 13 : 3 _ 6 _ s t 160 [)2 s : 10 12 17 i 100 I D3 15 ' 11 ' 7 ' 8 [ 240 ! Demand 180 Q 140 30 j 100 i_ 500 a) Solve the problem of supplying the outlets from the depots using Vogefs Approximation Method (VAM). b) Using the allocation solution generated in (a) apply the MODI method (closed-loop path) to determine the optimal allocation. c) Draw a network model to depict this problem. d) Formulate this transportation problem as a linear program. e) Model this problem in a spreadsheet and determine the shipment schedule that minimises total transportation cost. Compare your results with (a) and (b)