3. Solve distribution problem where there are 3 suppliers D1, D2 a D3 (central warehouses) and 4 customers O1, 02, 03 a 04. In the truck there can be only supply run for one customer. Limitation of suppliers is (D1-D3) 100, 160 and 140 trucks. Customer requirements are 60, 100, 80 a 75. Expenses of one supply run in the thousands Czech crowns between each supplier and customer is in the following table: 01 02 03 04 D1 8 12 20 9 D2 17 25 16 10 D3 5 7 11 19 Calculate basic expenses (by the method of north-west corner) and try to optimize. Compare results.