4) ) A mortgage balance of $137 960.70 is to be repaid over a eleven-year term by equal monthly payments at 8.1% compounded semi-annually. At the request of the mortgagor, the monthly payments were set at $1140.00. a) How many payments will the mortgagor have to make? b) What is the size of last payment? c) Determine the difference between the total actual amount paid and the total amount required to amortize the mortgage by the contractual monthly payments?