What is the electric potential energy in joules of two electrons

[BrianR84]

Homework Statement

(a) What is the electric potential energy in joules of two electrons separated by 2.43 nm?
(b) What would be it be if the separation was doubled?

Homework Equations

i think v=kq/r

The Attempt at a Solution

(a) 1.185 J
(b) 0.95 J

i can't figure out what I am doing wrong, I am following the book example.

 

[Dick]

I think it would be kq^2/r. kq/r is the electric potential from a single charge. You want to multiply by the other charge to get the potential energy. But in either event, I don't get what you are getting. Maybe you should tell us what numbers you are putting in.