Physics Work,Power & Energy Level: Misc Level

A 3.0 kg cart moving to the right with a speed of 1 m/s has a head-on collision with a 5.0 kg cart that is initially moving to the left with a speed of 2 m/s. After the collision, the 3.0 kg cart is moving to the left with a speed of 1 m/s. What is the final velocity of the 5.0 kg cart?