Answer:
200N
Step-by-step explanation:
The net force or resultant force on the object is obtained by adding all the forces acting on it.
In this case we have an upward force and a downward force, since they go in different directions they must have a different sign: we will define upward as positive and downward as negative:


The sign only to indicate that they are going in opposite directions, so the resulting force:

The net force acting on the object is 200N. (downwars due to the negative sign).