4. Consider a market where 100 firms are in operation in the short run. Each firm's cost function is TC= 450 + 2q2 . The market demand function is QD= 12005p.

a. Calculate the short-run market equilibrium (price and quantity).

b. Will there be entry or exit in the long run? (Suppose that demand and costs do not change.)

c. Calculate the long-run competitive equilibrium (price, quantity, and number of firms).