3. Two particles \(A\) and \(B\) are moving on a smooth horizontal plane. The mass of \(A\) is \(2 m\) and the mass of \(B\) is \(m\). The particles are moving along the same straight line but in opposite directions and they collide directly. Immediately before they collide the speed of \(A\) is \(2 u\) and the speed of \(B\) is \(3 u\). The magnitude of the impulse received by each particle in the collision is \(\frac { 7 m u } { 2 }\). Find

1. the speed of \(A\) immediately after the collision,
2. the speed of \(B\) immediately after the collision.