3) You take out a 40 year, $400,000 mortgage with constant payments at the end of each month and with interest rate i(12)=9%. After 30 years, you refinance the mortgage with a 10 year mortgage (also with constant payments at the end of each month) with an unknown interest rate i(12), but also pay an additional penalty of 5% of your outstanding balance at this time. Find i(12) if the payments for the last 10 years are $500 less than the payments for the first 30 years