Bond J has a coupon rate of 3 percent. Bond K has a coupon rate of 9 percent. Both bonds have 19 years to maturity, make semiannual payments, and have a YTM of 6 percent. If interest rates suddenly rise by 2 percent, what is the percentage price change of these bonds? What if rates suddenly fall by 2 percent instead? What does this problem tell you about the interest rate risk of lower-coupon bonds versus higher-coupon bonds?

Please show the formulas and explain each step :)