15. (0.2 point) A5 year, zero-coupon bond has a maturity of $1,000 and a present market price of $713. Its duration in years is (a) 4.7. (b) 5. (c) 4.2. (d) 3.9. 16.(0.5 point) A bond has a duration of 8 years and a present yield-to-maturity of 8%. If the yield-to-maturity rises to 10%, the approximate bond price change would be (a) +7.9%. (b) -25%. (c) 14.8%. (d) 12.9%. 17.(0.2 point) Positive convexity on a bond implies that (a) price increase at a faster rate as yields drop, than they decrease as yield increases. (b) the direction of change in yield is directly related to change to price. (c) price changes are the same for both increase and decrease in yields. (d) price increase and decrease at a faster rate than the change in yield. 18.(0.2 point) Which of the following statement about the Macaulay duration of a zero-coupon bond is true? The Macaulay duration of a zero-coupon bond (a) is equal to one-half the bond's maturity in years. (b) is equal to the bond's maturity in years divided by its yield to maturity. (c) cannot be calculated because of the lack of coupons