Coal is mined and processed at the following four mines in Kentucky, West Virginia, and Virginia:

Location Capacity (tons)

A. Cabin Creek 90 B. Surry 50 C. Old Fort 80 D. McCoy 60 280 These mines supply the following amount of coal to utility power plants in three cities:
Plant Demand (tons)
1. Richmond 120 2. Winston-Salem 100 3. Durham 110 330 The railroad shipping costs (in thousands of dollars) per ton of coal are shown in the following table. Because of railroad construction, shipments are prohibited from Cabin Creek to Richmond:
To (cost, in $1,000s)
From 1 2 3 A $ 7 $10 $ 5 B 12 9 4 C 7 3 11 D 9 5 7 Formulate this problem as a linear programming model and solve it by using the computer. LO.1