6. (12 points, 4 each) The market demand curve for a pair of duopolists is given as: P = 36 - 30, where Q is the total market demand. Each firm faces a constant marginal cost of $18 per unit. Assume that there are no fixed costs. a. The two firms form a joint monopoly with each firm producing an equal share of output. Find the equilibrium price, quantity, and profit for each firm. P. b. The partnership breaks up and the firms compete as Cournot duopolists. Find the + Cournot equilibrium price, quantity, and profits. t R c. Now, Firm 1 goes to price war with Firm 2. Find the Bertrand equilibrium price, quantity, and profits. tic