I'm warning you before i answer this i'm not guaranteeing i'm going to answer this wright but I'm pretty sure its bill pushed a car for 5 minutes for 20-km while doing 15 J of work. Why I think this is the answer is because it directly tells you the most information giving you the time it took him to move the object that distance and also telling you how many joule's of force he's exerting (power).
Hope this helped :)