A Restaurant Supply Company Must Ship at Least 60 Cases $\$ 7.20$

Essay

A restaurant supply company must ship at least 60 cases of lettuce to two midwest restaurants. Each restaurant can accommodate at most 60 cases of lettuce. Restaurant A already has 15 cases of lettuce on hand, while restaurant B already has 12 cases. It costs $\$ 7.20$ to ship a case of lettuce to restaurant A and $\$ 6$ to ship a case of lettuce to restaurant B. How many cases should be shipped to each restaurant to minimize cost? What is the minimum cost?