Final answer:
According to Newton's Third Law of Motion, since Francisco and Ethan exert a total force of 600 newtons on the car and it does not move, the car exerts an equal total reactive force. Thus, each person is pushed back with 300 newtons by the car.
Step-by-step explanation:
The question describes a scenario where Francisco and Ethan both exert an equal force on a car, with the total force being 600 newtons, but the car does not move. According to Newton's Third Law of Motion, for every action, there is an equal and opposite reaction. Since the car did not move, this implies that the total reaction force exerted by the car is equal to the total force applied to it, which is 600 newtons. Assuming the forces are shared equally, the car exerts a force of 300 newtons back on each person.
Therefore, the answer is A) 300 Newtons.