Compounded once a year: A=P(1+r)^t 2500=500(1+0.095)^t 1.095^t=5 because the unknown number is an exponent, use log to find the unknown: log(1.095^t)=log5 tlog1.095=log5 t=log5/log1.095 use your calculator, t=17.734 so this person is about 28 years old.
