A.A firm has two plants, one in the United States and one in Mexico, and it cannot change the size of the plants or the amount of capital equipment. The wage in Mexico is $5. The wage in the U.S. is $20. Given current employment, the marginal product of the last worker in Mexico is 100, and the marginal product of the last worker in the U.S. is 500.

a.Is the firm maximizing output relative to its labor cost? Show how you know.

b.If it is not, what should the firm do?

B.A firm is making a long-run planning decision. It wants to decide on the optimal size of plant and labor force. It is considering building a medium-sized plant and hiring 100 workers. Engineering estimates suggest that at those levels, the marginal product of capital will be 100 and the marginal product of labor will be 75. If the wage rate is $5 and the rental rate on capital is $10, is the firm making the right decision? Support your answer.

C.Carefully explain the difference between diseconomies of scale and diminishing returns.