Suppose that total cost of producing face masks for the typical firm is given by C(y) = 4y + y 2 . Thus, the marginal cost is MC(y) = 4 + 2y.

(a) Show that the supply curve of a firm is given by: S(p) = p 2 2.

(b) If the face mask industry is perfectly competitive and there are 200 identical firms in the market, show that the inverse market supply curve is given by: P = 200 + Q 100 , where Q is total industry quantity supplied