Suppose that the market demand is: P = 24 - 3Q, and marginal revenue is: MR = 24 - 6Q.

The marginal cost is: MC = 6 and fixed cost is 0.

a. If the market structure is monopoly, determine the profit maximizing price and output for this monopolist and calculate its economic profit or loss at the profit maximizing output.

b. If the market structure is perfect competition, determine the profit maximizing price and total output and calculate a typical firm's profit or loss at the profit maximizing output.

c. Which market structure is more efficient, i.e., monopoly or perfect competition? Also explain your answer in (c) diagrammatically.