(10 points) John purchased three assets to form a portfolio as follows: Asset A is a 100 par value zero-coupon bond maturing at par in 7 years that sells at a price to yield 3%. Asset B is a 100 par value bond with 4% annual coupons maturing at par in 9 years that sells at par. Asset C is a common stock paying a constant dividend of 20 into perpetuity that sells at a price to yield 8%. Calculate the duration of the portfolio at the time of purchase. (10 points) John purchased three assets to form a portfolio as follows: Asset A is a 100 par value zero-coupon bond maturing at par in 7 years that sells at a price to yield 3%. Asset B is a 100 par value bond with 4% annual coupons maturing at par in 9 years that sells at par. Asset C is a common stock paying a constant dividend of 20 into perpetuity that sells at a price to yield 8%. Calculate the duration of the portfolio at the time of purchase