If your money is in a stock mutual fund that you expect will average 8 a year, it will take you nine years to double your money (72 8 9). Using the rule of 72 to approximate how long it will take for an investment to double at a. For example, at 5 annual interest, it would take 20 years to double your. Find the total amount on deposit at the end of 4 years if the interest is. Continuous compounding means compound every instant, consider investment of 1 for 1 year. In this section we cover compound interest and continuously compounded interest. Christine invested 2500 for 4 years compounded semi-annually and.
2,000 is to reach 10,000 compounded quarterly at 6 in how long. An equation that represents kyras account balance after t years. This could be a starting investment, or the starting amount of a loan. The rule of 72 is a shortcut, or back-of-the-envelope, calculation to determine the. It will take approximately six years for johns investment to double in value. .