Answer:
18.9 years.
Explanation:
We have been given that Felicia put $85 into a CD that pays 3.8% interest.
We know that rule of 72 gives us the time it will take an amount to be double, when we divide 72 by the interest rate.
Upon dividing 72 by 3.8 we will get,


Therefore, it will take approximately 18.9 years for Felicia's money to double.