11.6. Suppose that United Airlines has a monopoly on the route between Chicago and Omaha, Nebraska.

During the winter (December–March), the monthly demand on this route is given by P ! a1 " bQ. During the summer ( June–August), the monthly demand is given by P ! a2 " bQ, where a2 # a1. Assuming that United’s marginal cost function is the same in both the summer and the winter, and assuming that the marginal cost function is independent of the quantity Q of passengers served, will United charge a higher price in the summer or in the winter?