Finite Math
posted by Matt on .
Kathy borrowed $800 at 6% interest. The amount of interest paid was $144. What was the length of the loan?

let the time be n years, assuming that compound interest is used.
800(1.06)^n = 944
1.06^n = 1.18
take log of both sides, and use log rules
n log 1.06 = log 1.18
n = log1.18/log1.06 = appr 2.84 years