pls step by step

3 A mortgage balance of $23 960 is to be repaid over a 7-year term by equal monthly payments at 6.8% compounded semi-annually. At the request of the mortgagor, the monthly payments were set at $440. a. How many payments will the mortgagor have to make? b. What is the size of the last payment? c. Determine the difference between the total actual amount paid through $440 payments and the total amount required through normal amortization at 6.8% to amortize the mortgage by the contractual monthly payments