John has an interest rate of \( 7.2 \% \) on his savings account. Using the Rule of 72 , his money will double in \( \square \) years.

Using the Rule of 72, you simply divide 72 by the interest rate to find out how long it will take for your money to double. In John's case, with an interest rate of \( 7.2\% \), it would take approximately \( 72 \div 7.2 = 10 \) years for his money to double. It’s a quick mental math trick that gives a good estimate without needing complicated calculations! This approach to estimating investment growth can be applied in various real-world scenarios, such as retirement planning or evaluating investment opportunities. For example, if someone wants to know how long it will take for their savings to grow significantly, they can use the Rule of 72 to make informed decisions on whether to invest in higher interest options or play it safe!