Suppose you plan to buy a house. You made a 10% down payment of $50,000 and took out a mortgage loan of $450,000 to pay for the remaining amount. The original terms called for 30 years of monthly payments at a 9% APR with the first payment due one month after you purchase the house. Ten years later, you got promoted, and your income increased. You now decide to make larger mortgage payments of $4,700. How long will you have to continue making payments to pay off your entire mortgage?