Chapter 4.3, Problem 20E

Supply Costs The chemistry department at a local college decides to stock, at least 900 small lest lubes and 600 large test tubes. It wants to buy at least 2700 test tubes to take advantage of a special price. Since the small test tunes arc broken twice as often as the large, the department will order at least twice as many small tubes as large.

(a) If the small test tubes oust 18 cents each and the large ones, made of a cheaper glass, cost 15 cents each, how many of each size should be ordered to minimize cost?

(b) Suppose the minimum number of test tubes is increased to 3000. Use shadow costs to calculate the total cost in this case.