Two small smooth spheres A and B, of equal radii and of masses 4 kg and m kg respectively, lie on a smooth horizontal plane. Initially, sphere B is at rest and A is moving towards B with speed 6 m s^-1. After the collision A moves with speed 1.5 m s^-1 and B moves with speed 3 m s^-1.

Find the two possible values of the loss of kinetic energy due to the collision.