A company has a portfolio of two bonds. each of which has annual coupons: Bond 1: 10-year annual coupon bond with face amount $200,000 and 7% coupon rate Bond 2: 20-year annual coupon bond with face amount $300,000 and 6% coupon rate The price and Macaulay duration for both bonds are calculated based on an annual effective interest rate of 6%. Calculate the price of each bond. Calculate the Macaulay duration of the bond portfolio. Calculate the estimated price of the bond, using the first-order Macaulay approximation, if the annual effective interest rate is changed to 7%