A certain retiree currently receives $15,000 a year in Social Security. Each year his payment is increase by 3% to keep up with inflation. How much will the retiree collect in benefits over the next seven years? (Count this year as the first of the seven years.)
sum of
15000 + 15000(1.03) + 15000(1.03^2 + ... for 7 terms
sum = a(r^2 - 1)/(r-1)
= 15000( 1.03^7 - 1)/(1.03-1)
= 114,936.93