9. Sara buys a 20-year bond. The bond has a face value of $10,000 and a redemption amount of $12,000. The bond pays semi-annual coupons and the amount of each coupon is $450. Sara buys the bond to yield a semi-annual (yield) rate of X%. The book value after the 15th coupon is $13,988.06. The amortization of premium in the 16th coupon is $45.72. (a) Find the interest part (also called interest earned) in the 16th coupon. (b) Find the value of the semi-annual yield rate X.