To finance his education, Chris took out student loans totalling $25,400. He consolidated these loans into a single loan with monthly payments for 10 years and an interest rate of 7.8%. After making payments for 7 years, his grandfather has graciously offered to pay off the remaining balance. Calculate the amount needed to pay off his loan. The amount needed to pay off this loan after 7 years is $ (Round to the nearest cent as needed.)