The complete equation is as follows:
Force between two charge particles = k * Q1 * Q2 / r^2,
where k is constant, Q1 is charge on 1 particle, Q2 is charge on the other particle and r is the distance between the particles.
From the equation, if one of the charges is doubled, then the force will also be doubled. It will become 7.6*2 = 15.2 Newtons.
