How to compute compounded interest rate ?

Question

I have the following scenario where i invest variable amount of principal every month,

Investment Month
$300       Jan
$200       Feb
$100       Mar

and i get a return of,

Returns    Month
$1000      Apr

How do i calculate the nominal annual interest rate if the amount is compounded monthly?

Answer 1

300*(1 + p/12)^(3) + 200*(1 + p/12)^(2) + 100*(1 + p/12)^(1) == 1000

Use bisection or something else to solve numericaly http://tinyurl.com/2455qsw

p=286%