a. Monthly loan payment:
$330,000 loan amount
25 year loan term
4.90% annual interest rate
Compounded monthly
Monthly interest rate = 0.0475% (4.90% / 12 months)
Monthly payment = $330,000 * (0.0475% * (1 - (1 / (1 + 0.0475%)^(25 * 12)))) / (1 - (1 / (1 + 0.0475%)^(25 * 12))) = $1,711.19 (rounded to the nearest cent)
b. Principal balance after 3 years:
Year 1: $330,000 * (1 - (1 / (1 + 0.0475%)^12)) = $309,644 (rounded to the nearest cent)
Year 2: $309,644 * (1 - (1 / (1 + 0.0475%)^12)) = $287,020 (rounded to the nearest cent)
Year 3: $287,020 * (1 - (1 - (1 / (1 + 0.0475%)^12))) = $264,148 (rounded to the nearest cent)
c. Extra payment of $50,000 at year 3:
Remaining principal balance after extra payment = $264,148 - $50,000 = $214,148
Time needed to pay off $214,148 at monthly payment of $1,711.19 =
$214,148 / $1,711.19 per month = 12 years (rounded up)
So amortization period shortened by 3 years.
In years and months:
3 years