Field A and field B of a mining company produce two types of coals. Both fields can produce coal-1 and coal-2. The operating cost ($ per day) for field A and field B are $55,000 and $45,000, respectively. Mining field A can produce 250 tons of coal-1 along with 300 tons of coal-2 coal per day whereas the mining field B can produce 200 tons of coal-1 along with 450 tons of coal-2 per day. The demand for coal-1 is expected to be 120,000 tons and for coal-2, it is expected to be 170,000 tons. The expected demand should be met.
a. Write out a linear programming model to minimize the operating costs of the mining fields and decide how many days the company needs to operate each of these fields.
b. Solve the model using Excel Solver and give the optimal days to operate each of the fields.
Please also be sure to show formulas in excel!