A 3-kg block moving at 4 m/s makes an elastic collision with a stationary block of mass

Question:

A 3-kg block moving at 4 m/s makes an elastic collision with a stationary block of mass 2 kg. Use conservation of momentum and the fact that the relative velocity of recession equals the relative velocity of approach to find the velocity of each block after the collision. Calculate the initial and final kinetic energies of each block.