The screw and bolt market contains many identical firms, each with a total cost function TC(q) = 400 - 5q + q 2 , marginal cost function MC(q) = - 5 + 2q , and average cost function AC(q) = 400 q - 5 + q , where q is the firm's annual output. The market demand curve for this industry is Q D = 262.5 - P 2 , Each firm in the industry is currently earning zero economic profit. How many firms are operating in this industry? What is the market equilibrium price in the long run