Consider a 15-year, 8% semi-annual coupon bond selling at 846.41 to give YTM = 10%. What is the duration of the bond? Suppose the interest rate instantaneously increases from 10% to 10.10%, then what is the approximately price change estimated using duration? What is the actual price change? Is there any difference? Explain. Now suppose the interest rate instantaneously increases from 10% to 12%, then what is the approximately price change estimated using duration? What is the actual percentage price change? Is there any difference? Explain.