A loan of $Z is to be fully repaid by 4n level annual repayments of $X made in arrears at a constant effective interest rate. Shortly after the (2n)-th repayment, the loan outstanding amount at that time is 80% of the original loan amount Z. (a) Calculate the proportion of the capital repayment in the (3n+1)-th repayment, that is, the value of capital repayment 3n+1 (6 marks) (b) Given that the total capital repayment of the first 3n level annual repayments is $28,000, calculate the value of Z and the total capital repayment from the (n + 1)-th annual repayment until the (3n)-th annual repayment. (6 marks) A loan of $Z is to be fully repaid by 4n level annual repayments of $X made in arrears at a constant effective interest rate. Shortly after the (2n)-th repayment, the loan outstanding amount at that time is 80% of the original loan amount Z. (a) Calculate the proportion of the capital repayment in the (3n+1)-th repayment, that is, the value of capital repayment 3n+1 (6 marks) (b) Given that the total capital repayment of the first 3n level annual repayments is $28,000, calculate the value of Z and the total capital repayment from the (n + 1)-th annual repayment until the (3n)-th annual repayment. (6 marks)