Two men (A & B), having weights of 120.0 lbs. and 150.0 lbs. , respectively, stand on a 300.0 lb. cart initially at rest. Each runs at a speed of 5.0 ft/s relative to the cart. Determine the speed of the cart if man A runs and jumps off, causing the cart to move with man B, and then man B jumps off the same end.