Total amount of money owed after three months = $22275 Total amount of money owed after 12 months = $18900 Amount of money repaid on 9 months = 22275 - 18900 = 3375 dollars Then Average payment rate on the principal = 3375/9 = 375 dollars I hope that the procedure is clear enough for you to understand and this is the answer that you were looking for. I also hope that the answer has come to your desired help.