Q. Consider two firms facing demand curve P = 50 - 5Q, where Q = Q1 + Q2. firms' cost functions are C1(Q1) = 20 + 10Q1 and C2(Q2) = 10 + 12Q2. A. Suppose both firms have entered industry. What is joint profit-maximizing level of output? How much will each firm produce? How would your answer change if firms have not yet entered industry?