PDF Simple Interest - Effortless Math 12) Sara puts $4,000 into an investment yielding 5% annual simple interest; she left the money in for five years. How much interest does Sara get at the end of those five years? $_____ how much interest will you earn in two years? $_____ 14) $400 interest is earned on a principal of $2,000 at a simple interest rate of 5% interest per year.