Answer: Fnet = 40 N on the right
Explanation: The net force is the summation of forces acting on an object. Add the forces in the same direction and subtract to the opposing force moving in the opposite side.
Fnet= F1 + F2 - F3
= 120 N + 60 N - 140 N
= 180 N - 140 N
= 40 N on the right