A mortgage for a condominium had a principal balance of $43,500 that had to be amortized over the remaining period of 8 years. The interest rate was fixed at 4.42% compounded semi-annually and payments were made monthly.

a. Calculate the size of the payments.

b. If the monthly payments were set at $688, by how much would the time period of the mortgage shorten? (in years and months)

c. If the monthly payments were set at $688, calculate the size of the final payment.