Physics
posted by Kelly .
Suppose now that the air carts below are both moving to the right initially. The cart to the left has a mass m1 and an initial speed v0; the cart to the right has an initial speed v0/2. If the center of mass of this system moves to the right with a speed 6/7 v0, what is the mass of the cart on the right?

(m1+m2)6/7 vo=m1*vo+m2*Vo/2
solve for m2 
Thanks! i was so close to that equation i just wasn't moving my total mass to the left side.