Erin purchases a retirement annuity that will pay her $2,000 at the end of every six months for the first ten years and $400 at the end of every month for the next seven years. The annuity earns interest at a rate of 2.1% compounded quarterly. a. What was the purchase price of the annuity? Round to the nearest cent b. How much interest did Erin receive from the annuity? Round to the nearest cent