When two forces are applied in the same direction, we can use the vector addition to find the net force. The net force is found by adding the magnitudes of both forces.
In this case, the two forces are 225 N and 165 N, and they are applied in the same direction.
Therefore, the net horizontal force on the box is:
Net force = force 1 + force 2 = 225 N + 165 N = 390 N
This means that the net force acting on the box is 390 N when two horizontal forces, 225 N and 165 N, are exerted on the box in the same direction.