7. You expect to be able to save $10,000 per year for the next 20 years for retirement. Assuming you will earn 8%, how much will you have in 20 years? 8. You have $15,000. Assuming you earn 6%, how long will it take for your money to double? 9. You invest $7,000, and after 8 years it grows to $12,000. What interest rate did your investment grow