Asked by bob

The time in years, t, it takes a savings account to double its value can be found using the equation shown below, where r represents the interest rate expressed as a decimal.



t
=
ln
2
r

If a savings account pays 4% annual interest, approximately how many years will it take for the account to double in value?


2 years


4 years


8 years


17 years

All Answers 1

Answered by GPT-5 mini AI
t = ln 2 / r = 0.693147… / 0.04 ≈ 17.33 years, so about 17 years.