FiberTech makes newsprint for newspapers at three mills, A, B, and C. The cost of producing newsprint is estimated to be $210 at mill A, $225 at B, and $220 at C. Five primary geographical markets are served from these mills. The monthly demand at each market, the shipping cost (per ton) between each mill and market, and the monthly production capacity of each mill are given in the table.

                            

FiberTech would like to assign production responsibilities to the mills, and also specify how much should be shipped from each plant to each market, so as to minimize total production and distribution costs.

(a) Formulate an LP to minimize total production and distribution costs.
(b) Set up and solve the problem on a spreadsheet.
(c) What is the optimal solution? Explain the rationale for the solution.