To determine the monopoly prices under price differentiation, we first need to determine the aggregate quantity supplied by the Acosta com- pany. To do so, we need to aggregate the individual demand curves. The aggregate (inverse) demand curve is given by: P =21.5Q Q0.667 P =1.40.6Q Q0.667 From the aggregate demand curve, we can determine the aggregate marginal revenue curve: MR=23Q Q0.333 MR=1.41.2Q Q0.333 Marginal cost are given by MC = 2Q2