Doug Bareak, a friend of yours, has recently purchased a home for $200,000. He paid $20,000 down and financed the remainder with a 20-year, 5% mortgage that is payable in blended payments of principal and interest of $1,290 per month. At the end of the first month, Doug received a statement from the bank indicating that only $540 of the principal was paid during the month. At this rate, he calculated that it would take over 28 years to pay off the mortgage. Explain why Doug is incorrect.