Answer
-40 Joules.
Work Step by Step
The particle is traveling from (f) to (i) and ends at (j). In the first segment, the force does -20 Joules of work on the particle.In the second segment, the force also does -20 Joules of work. Although it is labeled as positive 20 Joules, the particle is traveling in the opposite direction, so the sign must be flipped. The total work is -40 Joules.
