A group of students are performing an experiment in class using collision carts on a track. An 8.0 kg cart moving to the right at 4.0 m/s hits a 4.0 kg cart moving to the left at 6.0 m/s. Immediately after the collision, the 4.0 kg cart moves to the right at 3.0 m/s. What are the speed and direction of the 8.0 kg cart after the collision?