4. Transportation costs per unit from sources to destinations are as follows, and the corresponding demands and supplies are given. Set up as an LP problem. Source Warehouse 1 Warehouse 2 Warehouse 3 Supply Factory A $ 3.00 $ 4.00 $ 2.50 500 Factory B $ 6.00 $ 2.00 $ 3.50 500 Demand 400 400 400