An increase in the wage rate of steel workers will reduce the supply of steel.

Economists say that a firm has a normal profit when:

a. it earns a return of at least 10 percent. b. its accounting profit is positive. c. it can pay all its variable costs. d. its economic profit is zero.

Which of the following statements about isoquant maps is true?

A. They always have positive slope. B. They cannot illustrate economies of scale unless some numerical values are attached. C. They always have negative slope. D. They can illustrate diminishing returns to production only when they have numerical values attached.