please help!

15 Both Bond Sam and Bond Dave have 9 percent coupons, make semiannual payments, and are priced at par value. Bond Sam has five years to maturity, whereas Bond Dave has 18 years to maturity ts a. If interest rates suddenly rise by 2 percent, what is the percentage change in the price of Bond Sam and Bond Dave? (A negative answer should be indicated by a minus sign. Do not round intermediate calculations and enter your answers as a percent rounded to 2 decimal places, e.g., 32.16.) b. If rates were to suddenly fall by 2 percent instead, what would be the percentage change in the price of Bond Sam and Bond Dave? (Do not round intermediate calculations and enter your answers as a percent rounded to 2 decimal places, e.g., 32.16.) Answer is complete but not entirely correct. a. 7.92 X % % Bond Sam Bond Dave Bond Sam Bond Dave -17.66 7.92 17.66 b. % X % Mic Graw HI