Question 8

Maximum profit occurs when marginal revenue equals marginal cost and firms can earn economic profits in the short run.

Both monopolies, monopolistic competition, and perfect competition share the feature that maximum profit occurs when marginal revenue equals marginal cost. Additionally, these market structures allow firms to earn economic profits in the short run under certain conditions.

A) Maximum profit occurs when marginal revenue equals marginal cost.

This statement is correct as it applies universally across different market structures. In all three cases, firms determine their optimal output level where the additional revenue from selling one more unit equals the additional cost of producing that unit. This principle is fundamental to profit maximization in economics.

B) In the long run, new firms can easily enter the market.

This statement is incorrect for monopolies and partially incorrect for monopolistic competition. While perfect competition allows for easy entry of new firms in the long run, monopolies typically have significant barriers to entry that prevent new competitors from entering the market. Thus, this characteristic does not apply to all three market types.

C) The firm(s) can earn economic profits in the short run.

This statement is correct, particularly for monopolies and monopolistic competition. In the short run, firms can take advantage of market power and demand to earn economic profits. Perfect competition, however, typically sees firms earning normal profits in the long run due to market entry, but in the short run, they can also experience profits under certain conditions.

D) The structure does not produce welfare-maximizing level of output.

This statement is incorrect in the context of perfect competition, which is known for achieving the welfare-maximizing level of output where social surplus is maximized. While monopolies and monopolistic competition may not produce at this level, not all three structures share this feature.

E) The price of a unit is greater than the marginal cost.

This statement is generally true for monopolies and monopolistic competition, where firms have pricing power. However, in perfect competition, firms price at marginal cost. Therefore, this characteristic does not apply to all three market structures.

F) In the long run, it is nearly impossible for new firms to enter.

This statement is incorrect as it applies only to monopolies. Monopolistic competition allows for entry in the long run, and perfect competition ensures that new firms can enter freely. Thus, this feature does not apply universally.

Conclusion

The correct answer highlights that maximum profit occurs when marginal revenue equals marginal cost and that firms can earn economic profits in the short run. These principles are foundational to understanding profit maximization across different market structures. The other options fail to apply universally or accurately depict the characteristics of monopolies, monopolistic competition, and perfect competition.