Welfare mothers' desires for their children are quite high, but their expectations are much lower

You want to purchase two umbrellas. The price is $40 per umbrella, 2 for $60, 3 for $75. What will be the marginal cost to you of buying a third umbrella?

A) $75 B) $25 C) $20 D) $15 E) $10

In the long run, perfectly competitive firms make zero economic profit. This result is due mainly to the point that a perfectly competitive market has

A) few buyers and sellers. B) no barriers to entry and exit. C) price taking by the firms. D) firms with perfectly elastic market demand.