9.10. The bolt-making industry currently consists of 20 producers, all of whom operate with the identical short-run total cost curve STC(Q) ! 16 " Q2

, where Q is the annual output of a firm. The corresponding short-run marginal cost curve is SMC(Q) ! 2Q. The market demand curve for bolts is D(P) ! 110 # P, where P is the market price.

a) Assuming that all of each firm’s $16 fixed cost is sunk, what is a firm’s short-run supply curve?

b) What is the short-run market supply curve?

c) Determine the short-run equilibrium price and quantity in this industry.