Mechanics Problem; Any help would be appreciated

The details of the question are below;

Quote:

Identical Cars A, B and C, are initially at rest in a straight line on a horizontal surface with their brakes off. Car A is pushed towards the others so that it hits Car B with speed $\displaystyle {2ms^-1}$.

Given that the coefficient of restitution between any two cars is 0.75, find the speeds of the cars after all collisions have finished.

The answers are below;

Please bear in mind that this is college work (16-18) and so try to keep the explanations limited to that as much as possible.

Thanks in advance.