(c) Sally wishes to accumulate a sum of $400,000 in a retirement account by the time of her retirement 25 years from now. If she wishes to do this through monthly payments into the account that earn interest at the rate of 6% per year compounded monthly, what should be the size of each payment? (5 marks (d) John has RM50,000, 18 years mortgage at 7% compounded monthly. (i) Find the monthly payment? (5 marks) Suppose John decide to add an extra RM50 to his mortgage payment each month starting from the very first payment. How long will it take John to pay off the mortgage? (5 marks Continued