If there is a particle X of mass 3m which is moving with velocity Uion a smooth horizontal table and it collides with a particle Y of mass 5m which is at rest (and we are given that the coefficient of restitution between the particles is e, then how can I find the velocities of X and Y immediately after the collision in terms of e and u?

Also is there a way of showing the speed of X immediately after the collision does not exceed 3u/8 for all values of e?