The man moves farther and faster than the boy. The boy moves farther and faster than the man. The man moves farther but the same speed as the boy. The boy moves faster but the same distance as the man.
I gave my students this multiple choice question: A 60-kg man and a 25-kg boy, both on roller skates, push off of each other using their hands. Which of these describes the motion of the two people?

Only one answer is correct among these 4 choices:
- The man moves farther and faster than the boy.
- The boy moves farther and faster than the man.
- The man moves farther but the same speed as the boy.
- The boy moves faster but the same distance as the man.

Could you tell me which one is correct?

The boy moves farther and faster than the man.