posted by Lex .
suppose you invest 2500 and earn 4.2% annual interest, compounded quarterly. how long will it tak for your investment to double?
Solve this equation for the number of quarters, n.
[1 + (0.042/4)]^n = 2
1.0105^n = 2
n = 66.36
That many quarters is 16.58 years
You will have to wait for the first interest-paying date after 16.5 years.