Answer:
300 J
Step-by-step explanation:
First of all, we need to calculate the net force acting on the crate, which is given by:

where
F = 100 N is the horizontal push
is the force of friction
Substituting,

Now we can calculate the net work done on the crate:

where
d = 10 m is the displacement
Substituting,

According to the work-energy theorem, the kinetic energy gained by the crate is equal to the work done on it: therefore, the answer is 300 J.