*17. All book buyers have the same preferences, and under current arrangements, those who buy used books at $22 receive the same utility as those who buy new books at

$50. The annual interest rate is 10 percent, and there are no transaction costs involved in the buying and selling of used books. Each new textbook costs $m to produce and lasts for exactly 2 years.

a. What is the most a buyer would pay for the use of a new book for 1 yr?

b. How low would m have to be before a publisher would find it worthwhile to print books with disappearing ink—ink that vanishes 1 yr from the point of sale of a new book, thus eliminating the used-book market? (Assume that eliminating the usedbook market will exactly double the publisher’s sales.)