Force =
Constant x
Charge-A x charge-B
divided by
Distance-squared.
Constant = 9 x 10^9 N-meter^2/coul^2
Force = (9 x 10^9) (3 C) (2 C)
Divided by
(5 meters)^2.
= (9 x 10^9) (6 C^2) / (25 m^2)
= 2.16 x 10^9 Newtons .
That's 2,160,000,000 Newton's.
= about 485 million pounds
= about 243 thousand tons.
(One Coulomb is a very big charge !)