The MacLellans originally chose to make payments of $1,600 per month on a $138,000 mortgage written at 7.4% compounded semiannually for the first five years. After three years they exercised their right under the mortgage contract to increase the payments by 10%. a. If the interest rate does not change, when will they extinguish the mortgage debt? (Do not round the intermediate calculations.) The total time to pay off the loan is years and months. b. What will be the principal balance at the end of the five-year term? (Round your answer to the nearest cent.) Balance 2$