Two students pushes on a box in the same direction, and one pushes In The opposite direction. what is the net force on the box if each pushes with the force of 50N?

If they are both pushing with the same force but in opposite directions,

and if there are no other forces on the box besides them pushing, then

the net force on the box is zero and it just lays there, as if there were

no forces on it at all.