Elena's parents decide to invest $5000 into a college savings fund when she is born. If the account earns an interest rate of 7% per year, how many years will it take for the account to have $28,000?

Answer 1

28000 = 5000(1.07)^t

28/5 = 1.07^t

log(28/5) = tlog(1.07)

t = log(28/5)/log(1.07)

t = 19 years