Sand and Gravel Company provides topsoil for three residential housing developments. Topsoil can be supplied from three different farms as follows: Farm Weekly capacity (cubic meter) A 100 B C 150 125 Demand for the topsoil generated by the three customers is given below: Customer Weekly demand (cubic meter) 1 50 2 3 150 300 The manager of the Sand and Gravel has estimated the cost per cubic meter to ship over each of the possible routes as follows: To Customer 1 Customer 2 Customer 3 From Farm A 4 2 Farm B 5 1 Farm C 7 6 a. Draw the network diagram to represent this problem. 8 93 3 b. Formulate an LP to decide the shipment of topsoil to customers at the minimum cost. Decision variables: Objective function: 22 RATO tv