Question 3: (15 marks) Kelsey and Blake are thinking of purchasing a house. The house costs $320,000 and they have saved $80,000 as a down payment. The rest will be secured by a mortgage. The bank is offering a 25-year mortgage with a term of 5 years at a rate of 7% (APR) requiring monthly payments. a) Calculate the amount of each payment. b) Calculate the monthly payments if they are made at the beginning of the month rather than the end. c) If Kelsey and Blake can only afford to pay $1,500 each month, how much would the bank allow them to borrow? (These payments are made at the end of each month) d) Assuming they secure the mortgage in part (c), how much of the 81'st mortgage payment is principal and how much is interest