math
posted by Anonymous .
You are borrowing $90,000.00 at an annual rate of 5% for 20 years .
What is the total amount you will pay ?

Are you paying off the loan in 20 years? In equal amounts? Are the payments monthly? If so, use an amortization formula.
This website, or hundreds of others easily found, may be helpful:
http://www.amortizationformula.org/