A $2\,\text{kg}$ ball moving at $24\,\text{ms}^{-1}$ undergoes inelastic head-on collision with a $4\,\text{kg}$ ball moving in the opposite direction at $48\,\text{ms}^{-1}$. If the coefficient of restitution is $2/3$, their velocities in $\text{ms}^{-1}$ after impact are