Answer:
Clarification:
Based on the given
the skateboarder's speed is 4.1 m/s
Force 
time=20 s
Since the movement is along the x direction, we will consider only the x component of force since there is no movement in the y direction.
The work done equals
The work done on the skateboarder by the rope is 1148 J 
and the work done on the cyclist by the rope is -1148, as the skateboarder's velocity is opposite the direction of the applied force