A small, 300 g cart is moving at 1.90 m/s on an air track when it collides with a larger, 2.00 g cart at rest. After the collision, the small cart recoils at 0.820 m/s. What is the speed of the large cart after the collision?

Answer 1

You will have to use conservation of momentum
Momentum1+Momentum2=momentum1'+momentum2'
300*1.90+0=300(-.820)+Massother*V

You list the other as "larger" 2g..which is not larger. At any rate, solve for v2'