The wood-pallet market contains many identical firms, each with the short-run total cost functionSTC(Q) = 400 + 5Q+Q2:
whereQis the firm's annual output (and all of the firm's $400 fixed cost is sunk). The corresponding marginal cost function isSMC(Q) = 5 + 2Q. The market demand curve for this industry isD(P) 262.5 -P/2, wherePis the market price. Each firm in the industry is currently earning zero, economic profit. How many firms are in this industry, and what is the market equilibrium price?