Momentum — practice question

Particles $A$ and $B$, whose masses are $3.2\text{ kg}$ and $2.4\text{ kg}$ respectively, rest on a smooth horizontal table. $A$ travels towards $B$ at a speed of $v\text{ m s}^{-1}$ and then strikes $B$, which is travelling towards $A$ at a speed of $6\text{ m s}^{-1}$. After the collision, both particles are at rest.