5. A bond's rating provides a guide to its price. As we write this in 2009, Aaa bonds yield 5.45% and Baa bonds yield 8.67%. If some bad news causes a 10% five year bond to be unexpectedly downrated from Aaa to Baa, what would be the effect on the bond price? (Assure annual coupons with face value $1,000) (10 分)