Johnny invests $2,745 into an account, which has been earning interest for many years and he now has a total of $39,974. In two sentences explain why a negative number would be reasonable in the solution of the rate he received on his investment?

1 Answer
Jun 22, 2018

The "effective" annual interest rate may need to be reported.
Rearranging the formula for compound interest to find the effective interest rate would invoke a "negative" number in the equation.

Explanation:

Rearranging the formula for compound interest to find the effective interest rate would invoke a "negative" number in the equation.

r=(FVPV)1n1

r=(399742745)1n1

r=(14.562)1n1

So, if the time lapse was 30 years, the rate would have been:
r=(14.562)1301=0.0932 or 9.32%