Here are some drills for you on finding market supply functions from linear firm supply functions. The trick here is to remember that the market supply function may have kinks in it. For example, if the firm supply functions are s1(p) = p and s2(p) = p − 2, then the market supply function is S(p) = p for p ≤ 2 and S(p) = 2p − 2 for p > 2; that is, only the first firm supplies a positive output at prices below $2, and both firms supply output at prices above $2. Now try to construct the market supply function in each of the following cases.

(a) s1(p) = p, s2(p) = 2p, s3(p) = 3p.

(b) s1(p) = 2p, s2(p) = p−1.

(c) 200 firms each have a supply function s1(p) = 2p − 8 and 100 firms each have a supply function s2(p) = p − 3.

(d) s1(p) = 3p−12, s2(p) = 2p−8, s3(p) = p−4.