You're investing $$5,600$ in a friend's new business, and she's promised that you'll receive a $100\%$ return $($that is$,$ you'll receive double your initial investment$).$ If you assume an interest rate of $8\%,$ how long will it take to reach that goal?You're investing $$5,600$ in a friend's new business, and she's promised that you'll receive a $100\%$ return $($that is$,$ you'll receive double your initial investment$).$ If you assume an interest rate of $8\%,$ how long will it take to reach that goal?