# Two point charges with electric potential energy?

## Homework Statement

"Two point charges 2.0cm apart have an electric potential energy -180 microJoules. The total charge is 31 nC. What are the two charges?"

V= k * q / r

## The Attempt at a Solution

I understand that V = -180 * 10^-6, k = 9*10^9, r = 0.02m, and the TOTAL q=31*10^-9 C....but what does that leave us to solve, in this equation? I know we need to find the total charge of the both of them individually, but I don't know how to break this equation up to do that. Can anyone help me see this through?

Hi netsurfer.
Let $$q_{1}$$ and $$q_{2}$$ be the charges you are asked to find.
How do these charges enter in your equation ?

Exactly, lol...I mean, I would think maybe if you cut the potential in half then solve for q then q1 and q2 would be equal? But that doesn't seem right at all... I'm a bit confused. How would I go about doing it?