A box is pushed with a constant force of 300 N. The frictional force acting between the box and the surface is 100 N. What is the net force acting on the box?

A 200 N.

explanation

Use the equation:
Net Force = Force (right) + (-) Force (left)
Insert values:
Net Force = 300 N + (-) 100 N
Solve:
Net Force = 200 N