A 70 kg man pushes a 50 kg man with the force of 50N. How much force has a 50 kg man pushed the other person?

Answer: Option A

Understanding Newton's Third Law:
Newton's Third Law of Motion states that for every action, there's an equal and opposite reaction.

Let's break down the question:
A 70 kg man (let's call him Man A) pushes a 50 kg man (Man B) with a force of 50N.
This 50N force is the 'action'.

According to Newton's Third Law, Man B will push back on Man A with an equal and opposite force.
This means Man B also pushes Man A with a force of 50N.

Therefore, the answer is A: 50N
The masses of the men are irrelevant to the force of the reaction; only the action force matters when applying Newton's Third Law.