A bakery sells loaves of whole wheat bread and loaves of rye bread. From past experience, the number of loaves of each type of bread sold daily is at least 10 but no more than 30. To prepare the loaves for baking, the baker needs (on the average) 3 minutes for a wheat bread and 2 minutes for a rye bread. There are at most 2 hours available daily for the baker to prepare the loaves. How many of each type should be prepared to maximize the daily profit, if there is 90 cents profit on a wheat bread, and 80 cents on a rye bread?
