Answer:
8 years.
Explanation:
We have been given that an investment account pays 8.0%, compounded annually. We are asked to find the number of years it will take for the investment to grow to $9,140.20, if you invest $5,000 today.
We will use compound interest formula to solve our given problem.
, where.
A = Final amount,
P = Principal amount,
r = Annual interest rate in decimal form,
n = Number of times interest is compounded per year,
t = Time in years.

Upon substituting our given values in above formula, we will get:





Now, we will take natural log of both sides.

Using log property
, we will get:



Therefore, it will take approximately 8 years for the investment to grow to $9,140.20.