10. Suppose the bond in number 9 just paid its 10th coupon (i.e., it has 350 payments left). What is the price if market rates have risen to 8.86%?
\[ \text{Price} = \$62,561.26 + \$7,617.87 = \$70,179.13 \]

11. You notice that a bond rises in price from \$1000 to \$1064.18 when rates go from 10% to 9%. What is the duration of this bond?
\[ \text{Duration} = 7.06 \]

12. A bond has a duration of 4.2 years. If interest rates fall by 50 basis points from an initial rate of 8.2 percent, what is the expected return on the bond?
\[ \text{Expected Return} = +1.94\% \]

13. Calculate the duration of a bond paying a 7% annual coupon with a market rate of interest of 9%, \$1000 face value, and a maturity of three years.
\[ \text{Duration} = 2.80 \text{ years} \]

14. Calculate the duration of a bond paying an 8% annual coupon with a market rate of interest of 9%, \$1000 face value, and a maturity of three years.
\[ \text{Duration} = 2.78 \text{ years} \]

15. Calculate the duration of a bond paying a 9% annual coupon with a market rate of interest of 9%, \$1000 face value, and a maturity of four years.
\[ \text{Duration} = 3.53 \text{ years} \]

16. Calculate the duration of a bond paying a 7% annual coupon with a market rate of interest of 10%, \$1000 face value, and a maturity of three years.
\[ \text{Duration} = 2.80 \text{ years} \]

17. Calculate the duration of a bond paying a 7% annual coupon with a market rate of interest of 12%, \$1000 face value, and a maturity of four years.
\[ \text{Duration} = 3.59 \text{ years} \]

18. Calculate the duration of a bond paying an 8% semi-annual coupon with a market rate of interest of 10%, \$1000 face value, and a maturity of two years.
\[ \text{Duration} = 1.885 \text{ or } 1.89 \text{ years} \]

19. Calculate the duration of a bond paying an 8.40% semi-annual coupon with a market rate of interest of 6.6%, \$1000 face value, and a maturity of two-and-a-half years.
\[ \text{Duration} = 2.31 \text{ years} \]