Supermarket checkout lines all tend to be roughly the same length. Why is that? Explain your answer using one or more concepts related to perfect competition and/or monopoly. (Note that this question is about the checkout lines within a particular store – the question is not about the number of supermarkets or grocery stores.)

Suppose that the demand curve for a good is P = 100 – 2Q. The marginal cost curve of a firm in the industry is given by MC = 3Q. Calculate and compare the equilibrium price and quantity under monopoly and perfect competition.

Which of the following statements about monopolies are correct? There is more than one correct answer to this question. You must mark all of the correct answers to receive full credit for this question. OAt the profit maximizing output for a monopoly, P< MR. OMonopolies are always illegal in the U.S. O If a firm enjoys decreasing returns to scale, this may help it to become a monopoly. In a pure monopoly, the firm is the industry. O A patent can help a firm to become a monopoly.

Which of the following is considered a barrier to entry in a monopoly? A. Control of a key resource B. Perfect information C. Many sellers in the market D. Price competition