Question: Production the James MacGregor Mining Company owns three mines: I, II, and III. Three grades of ore, A, B, and C, are mined at these mines. For each grade of ore, the number of tons per week available from each mine and the number of tons per week required to fill orders are given in the following table.
![270_Ore.png](https://secure.tutorsglobe.com/CMSImages/270_Ore.png)
Find the number of days the company should operate each mine so that orders are filled at minimum cost. Find the minimum cost.