A variable-rate mortgage of $ is amortized over years by equal payments. After months the original interest rate of % compounded was raised to % compounded . years after the mortgage was taken out, it was renewed at the request of the mortgagor at a fixed rate of % compounded for a four-year term.

(a) Calculate the mortgage balance after months.

(b) Compute the size of the new payment at the % rate of interest.

(c) Determine the mortgage balance at the end of the four-year term.

Round the final answer to the nearest cent as needed. Round all intermediate values to six decimal places as needed.)