Using bond prices to calculate duration and convexity: A 20-year bond with a 6.5% coupon paid semiannually has a yield of 6.24%.

(Ignore the % sign, so if your answer is 5.1234%, then enter your answer as 5.1234) (Be precise to 3 decimals.)

a. Using the approximate modified duration and approximate convexity computed above, compute the approximate percentage change in bond price when the bond yield increases to 7.74%.

b. Compute the exact percentage change in bond price when the bond yield increases to 7.74%.