a. What is the duration of a four-year Treasury bond with a 5.5 percent semiannual coupon selling at par? (Do not round intermediate calculations. Round your answer to 2 decimal places. (e.g., 32.16))

b. What is the duration of a three-year Treasury bond with a 5.5 percent semiannual coupon selling at par? (Do not round intermediate calculations. Round your answer to 2 decimal places. (e.g., 32.16))

c. What is the duration of a two-year Treasury bond with a 5.5 percent semiannual coupon selling at par? (Do not round intermediate calculations. Round your answer to 2 decimal places. (e.g., 32.16))