4. (50 points) Let's consider a Cournot competition. Inverse demand is given as P = 100 - 2Q and cost function for each supplier is C(q ) = 10+10q. There are two suppliers (in other words, i = 1, 2, q1+q2= Q) (a) Depict the reaction curves of supplier 1 and 2. (b) Derive equilibrium price(P*), market level quantity(Q*) and quantities for individual suppliers (qi* and q2*). (c) Calculate the price elasticity of demand at equilibrium quantity and price. (d) Calculate Lerner-index for individual supplier. (e) Derive equilibrium market price when one more supplier who has a same cost function as existing firms enters into the market(i.e., when there are 3 suppliers in the market)