Answer:
The 8.0 kg cart's direction is going towards the right, and its speed is 0.50 m/s.
Step-by-step explanation:
First the 8.0 kg cart is double of the other. Then the speed of the 8.0 cart 1.5 m/s slower than the other. Then after the collision the 4.0 kg cart goes half its old m/s ( 6 m/s --> 3 m/s ). Put on a diagram, refer to the picture ( sorry about my handwriting ).
Then it will be a total of 0.50 m/s.