0 N, 10 N, 100 N, or 200 N.

I solved if F=mg then F=10*10 or 100 N downward force. Therefore an upward force of 100 N resistance would be required. Why is the answer 200 N? Answer book says you want a net force of mg=100 N upwards but I'm not sure why 200 N upward is equal to a magnitude of g, which is only 100 N downward. What am I missing here?

Leigh