In 2013 and 2014, a federal judge ruled that Apple colluded with five major U.S. publishers to drive up the prices of e-books(which could be read on Apple's Ipad). Apple collects 30% commission on the price of a book from the publisher. Why would Apple want to help publishers raise their price? Given Apple's commission, what price would a book cartel want to set? (HINT: the marginal cost of an e-book is virtually zero)