Answer:
A) Wn = 90J
B) W1 = 100J
W2 = 10J
Step-by-step explanation:
A) The net work done on the box is calculated by using the following formula:
(1)
F1 = 100N
F2 = 10N
d: distance on which the box is moved = 1m
You replace the values of the parameters in the equation (1):

The net work on the box is 90J
B) The total work done by each force is:

The first box does a work of 100J and the second force does a force of 10J