The production and cost function of a perfectly competitive firm that produces good x in a perfect competition market structure in the short-run are shown below.

K	L	TP or Q	TC	ATC	MC
7.75	7	321	225	75/107	-
7.75	8	329	235	5/7	1.25
7.75	9	332	245	245/332	10/3
7.75	10	333	255	255/331	10

PK=20, PL=10

a. What is the output profit-maximizing level of the firm in the short-run, if the market price of good x is 3.33? In no more than three sentences, explain why.

b. How much is the maximum (economic) profit that the firm can earn in the short-run?

c. In the long run, how much economic profit does the firm earn? Why?