The table shows the results from an experiment designed to measure the momentum of two marbles, both before and after a collision. A fifth experiment is run, and the pre-collision momentum of marble 1 is 20 units. The total post-collision momentum is 40 units. What is the post-collision momentum of marble 1?

5 units.

10 units.

Without more data about the pre-collision conditions, it is impossible to say.

Without more data about the post-collision conditions, it is impossible to say.