How to calculate distance object traveled in completely inelastic collision?

pebbles

Ok, so I have this practice problem: a mass of 5 kg has hit a ball at 8 m/s. The ball it hit has a mass of 7 kg. What is the distance the ball traveled?


It's really frustrating when my notes don't go over ANY of this.

Galileo

Are you sure that's the entire problem statement? It doesn't make much sense as it is.
Distance travelled as in: how far from the moment of impact till it hits the ground? That would depend on the height at which the collision took place.