Assume that in a perfectly competitive market each firm has the same cost structure. Such that in the long-run (at the optimal scale) each firm has the following average cost function A C=q2 -20q+120.

If total market demand is given by Q=1500- 50P;

a. What would be the long-run equilibrium price and equilibrium output in this market?

b. How many firms would operate in the long-run?

Explain your answers & show your calculations.