3) Randi can get: a fully amortizing 30 year fixed rate mortgage with monthly payments for $500,000 at an annual interest rate of 9%, compounded monthly. Or a fully amortizing 15 year fixed rate mortgage with monthly payments for $500,000 at an annual interest rate of r, compounded monthly. What does the interest rate on the 15 year fixed rate mortgage need to be so that Randi s payment on the 15 year fixed rate mortgage is the same as the 30 year fixed rate mortgage?