Answer:
≈ 18 years
Step-by-step explanation:
Given the principal amount of $500 used to invest in a CD, possibly earning an interest of 4%:
<h3><u>Rule of 72, Defined:</u></h3>
The rule of 72 states that the time, <em>t</em>, it takes to double one's money is given by .
In other words, the rule implies that you could easily find the approximate number of years that it will take to double your money by simply dividing 72 by the given interest rate (in percentage), 4%.
<h3><u>Solution:</u></h3>
Substitute the interest rate into the rule of 72 to find the time it takes to double one's savings:
Therefore, it will take approximately 18 years to double your savings of $500.