Question

Lucinda put $ 66 into a CD that pays 5.7% interest. According to the rule of 72, approximately how long will it take for her money to double?

Answer 1

Do you know what the 72 rule is?

In simple terms, it is a calculation used to see how long it will take for your money to double at a specified rate. Represented as:

\[\large t \approx \frac{72}{r} \]
where t is the time it would take.
and r is the specific rate

So in your case, it would look something like this:
\[\large t \approx \frac{72}{5.7}\]

This will give you the amount of time (in years) that it would take for the $66 to double.