A block of mass m = 5.6 kg- moving on a frictionless surface with a

A block of mass m = 5.6 kg, moving on a frictionless surface with a velocity of 6.5 m/s to the right, collides with a block of mass 10.0 kg at rest, as shown in the figure. After the collision, the 5.6-kg block recoils with a velocity of 0.70 m/s to the left. What is the initial velocity of the 10.0 kg bock immediately after the collision?