Question

You invest $5,000 at a 12% annual return that is compounded quarterly. That means that your interest earned is calculated and added to your account 4 times a year.

When would your investment double in value?

Answer 1

2 = (1+.12/4)^(4t)
t = 5.86 years,

or 6 years, since at 5.75 years the amount hasn't quite doubled.