Instructions:
Students should perform an ability to formulate the problem properly, and solve it graphically using a method of corners.
Problem: A company makes specialty calculators at two plants. The eastside plant can produce 80 nursing calculators and 40 business calculators in one day at a total cost of $500. The west side plant can produce 40 nursing calculators and 40 business calculators in one day at a total cost of $400. Find the number of days each plant should operate to minimize the cost of filling an order for 700 nursing and 400 business calculators within 12 days.