Simple electric field strength problem

[liamporter1702]

Homework Statement

How far away from a 360μC charged particle is the electric field strength 49mN/C?

Homework Equations

E=(8.99x10$^{9}$ x $\frac{Q}{r^{2}}$

The Attempt at a Solution

I assumed it would be a simple case of rearranging the equation to give r=$\sqrt{\frac{8.99x10^{9}xQ}{E}}$ but after doing this and subbing in the values I got a value of 8127, which is clearly not correct. The answer that has been given is 186mm but I can't see the solution.

 

[liamporter1702]

Could it be a case of the answer given is not correct?