5. (Bond valuation) You own a bond portfolio that pays $200 in annual interest, with a $10,000 par value. They mature in 15 years. Your required rate of return is 11 percent. a. Calculate the value of the bond portfolio. b. How does the value change if your required rate of return (1) increases to 13 percent or (2) decreases to 8 percent? c. Explain the implications of your answers in part b as they relate to interest rate risk, premium bonds, and discount bonds. d. Assume that the bond matures in 5 years instead of 15 years. Recompute your answers in part b. e. Explain the implications of your answers in part d as they relate to interest rate risk, premium bonds, and discount bonds.