Final answer:
To produce a net force of 200 N on a sled, a 300 N force and a 100 N force can combine if there is an opposing force of 200 N acting in the opposite direction.
Step-by-step explanation:
In order to calculate the net force acting on the sled, we need to add the individual forces together. The 300 N force and the 100 N force are acting in the same direction, so we can simply add them together. 300 N + 100 N = 400 N. However, the question states that the net force on the sled is 200 N, so this means that there must be another force acting in the opposite direction. This opposing force must have a magnitude of 200 N in order for the net force to be 200 N.