3. Two firms are Cournot competitors facing the demand curve Q = 42 - P. Firms have constant marginal costs of $6 and zero fixed costs. a. What is the Cournot Equilibrium of this industry (prices, outputs and profits)? b. Suppose that firm B has marginal costs to $18. (while the A's is still $6). Now, what is the Cournot Equilibrium of this industry? c. How did firm A benefit from firm B's higher costs