A $$1 \mathrm{~kg}$$ ball moving at $$12 \mathrm{~ms}^{-1}$$ collides with a $$2 \mathrm{~kg}$$ ball moving in opposite direction at $$24 \mathrm{~ms}^{-1}$$. If the coefficient of restitution is $$2 / 3$$, then their velocities after the collision are

A ball hits the floor and rebounds after an inelastic collision. In this case