How much should you invest each month in order to have $300,000 if your rate of return is 8% compounded monthly and you want to achieve your goal in 40 years? $ How much interest will you earn? $ How much should you invest each month in order to have $300,000 if you want to achieve your goal in 20 years? $ If you deposit the amount you need to achieve your goal in 20 years, how much will your savings be worth after 10 years?