B16. (Interest-rate risk) Philadelphia Electric has many bonds trading on the New York Stock Exchange. Suppose PhilEl’s bonds have identical coupon rates of 9.125% but that one issue matures in 1 year, one in 7 years, and the third in 15 years. Assume that a coupon payment was made yesterday. a. If the yield to maturity for all three bonds is 8%, what is the fair price of each bond? b. Suppose that the yield to maturity for all of these bonds changed instantaneously to 7%. What is the fair price of each bond now? c. Suppose that the yield to maturity for all of these bonds changed instantaneously again, this time to 9%. Now what is the fair price of each bond? d. Based on the fair prices at the various yields to maturity, is interest-rate risk the same, higher, or lower for longer- versus shorter-maturity bonds?