Alan and Hilda are clerks at a department store. The store pays each clerk $10 per hour for a basic eight-hour day, $15 per hour for overtime of up to four hours, and also $20 for overtime exceeding four hours a day.

a)Alan works 10 hours a day. What are his: (I) marginal pay; and (II) average pay?

b)Hilda works 14 hours a day. What are her: (I) marginal pay; and (II) average pay?

c)Under what pay structure would the marginal pay be less than the average pay?