Answer is at the bottom.

Luke takes out a loan of S50,000 for a term of15 yearyat an annual effective interest rate of 4%/ Luke is to pay the bank quarterly payments of interest only until the end of the 15th year when the $50,000 must also be repaid. Luke makes a deposit at the end of each year into a sinking fund earning 3% annual effective interest. At the time of the 16th interest payment, Luke and the bank agree to terminate the loan. Luke makes that interest payment and also repays the entire principal, applying the balance in the sinking fund immediately before the 16th interest payment is due (and before the 4th sinking fund deposit is made) What additional amount (including interest due) must Luke pay in order to pay off the entire loan