Final answer:
The net force exerted on the desk when one person applies a force of 120 N and another applies a force of 150 N in the same direction is 270 N.
Step-by-step explanation:
When you exert a force of 120 N on an object and your friend exerts 150 N in the same direction, the forces add together to result in a net force. The combined force is calculated by simply adding the two forces together: 120 N + 150 N = 270 N. Thus, the net force you and your friend exert on the desk is 270 N.