049 Effective annual interest rate, repayments and loan terms Don and Jenny wish to borrow $180 000, to be repaid over a period of 20 years by monthly instalments. The interest rate is 7.8 per cent per annum. The rst payment is due at the end of the rst month. a) Calculate the effective annual interest rate. b) Calculate the amount of the monthly repayment if the same amount is to be repaid every month for the period of the loan. c) Suppose, instead, that the lender agrees that Don and Jenny will repay $ 1 100 per month for the first 12 months, then $ 1250 per month for the 12 months after that, then $X per month thereafter. Assuming that the term is to stay at 20 years, how much is $X