Work is defined as Force x Distance.
W = F x D
We have 200n and 20m.
Since we have our force and distance, let's plug them in.
W = 200 x 20 (200n = F, 20m = D)
Multiply 200 by 20 to get our Work done.
200 x 20 = 4000.
We have 4,000J of work (J is our SI Unit of Work for Joules).
I hope this helps!