The following question appears to be extremely straight forward, but I can't seem to be able to obtain the correct answer.

The question is:

> 
> A charge Q1 = 1.3uC is at rest and is located 2.3 cm away from another
> fixed charge Q2 = 1.6uC. The first charge is then released. Calculate
> the kinetic energy of charge Q1 when it is 5.7 cm away from charge Q2.
> 
> 
> 

My solution is as follows:

> 
> Let r = 0.023 m r' = 0.057 m
> 
> 
> PE + KE = PE' + KE'
> 
> 
> But, KE = 0, so:
> 
> 
> KE' = PE' - PE
> 
> 
> KE' = (Q1$\times$V1) - (Q1$\times$V1')
> 
> 
> KE' = (Q1 $\times \frac{k \times Q2}{r}$) - (Q1 $\times \frac{k \times Q2}{r'}$)
> 
> 
> KE' = 0.49 J
> 
> 
> 

I've tried many times to check my substitutions and unit conversions and the answer still remains incorrect. It may be possible that I'm completely using the wrong method. Can anyone please make any suggestions or corrections?