if a person earns an annual interest rate of 4% on a savings account, how many years will it take for the…

if a person earns an annual interest rate of 4% on a savings account, how many years will it take for the persons money to double?\no 18 years.\no 20.4 years.\no 24 years.\no 28 years.
Answer
Explanation:
Step1: Use the rule - of - 72 formula
The rule - of - 72 formula for estimating the time $t$ it takes for an investment to double at an annual interest rate $r$ (in percentage) is $t=\frac{72}{r}$.
Step2: Substitute the interest rate
Given $r = 4%$, substitute $r$ into the formula: $t=\frac{72}{4}$.
Step3: Calculate the result
$t = 18$ years.
Answer:
18 years