The force of electrical interaction between two point charges is F. how will the modulus of the force

The force of electrical interaction between two point charges is F. how will the modulus of the force of interaction between bodies change if the charge of each is increased by 3 times?

Given:

q1, q2 – electric charges;

r is the distance between charges;

F is the force of interaction between charges;

q3 = 3 * q1, q4 = 3 * q ^ 2 – each charge was increased by 3 times.

It is required to determine F2 / F – how the force of interaction between charges will change.

In the first case, the force of interaction will be equal to:

F = k * q1 * q2 / r ^ 2, where k is a coefficient depending on the choice of the system of units.

In the second case, the force of interaction will be equal to:

F2 = k * q3 * q4 / r ^ 2 = k * 3 * q1 * 3 * q ^ 2 / r ^ 2.

Then:

F2 / F = (k * 3 * q1 * 3 * q ^ 2 / r ^ 2) / (k * q1 * q ^ 2 / r ^ 2) = 3 * 3 = 9 times.

Answer: the strength of interaction will increase 9 times.