The interest rate for the first four years of a $31,000 mortgage loan was 3.65% compounded semiannually. The monthly payments computed for a 8 -year amortization were rounded to the next higher \$10. (Do not round intermediate calculations and round your final answers to 2 decimal places.) a. Calculate the principal balance at the end of the first term. Principal balance $ b. Upon renewal at 6.15% compounded semiannually, monthly payments were calculated for a four-year amortization and again rounded up to the next $10. What will be the amount of the last payment? Final payment $