Precalc
posted by Amy on .
What annual rate of interest is required to double an investment in 3 years?

i tried solving this but got .23 instead of 26%

I know at 7% interest an investment will double in 10 years, but this doesn't help you.
let me see what I can find
is your problem simple interest? 
I think so, yes A = Pe^(r)(t)

please help