Simple and genius.

Approximately once a week a friend recruits a team of young guys to unload/load cars in the warehouse. He is given a certain amount, he recruits three from the category of 25-30 years and five 16-17, because among them there are more willing (and they are willing to work for a smaller amount). Also sometimes among them appears a young girl, looking like the same 16 years old. Not to say that she has a strong body, but tries to work equally with everyone, except that she is usually left with lighter objects. I once after loading asked her what motivated her to go here, because the girls are not especially in the loads. It turned out that the organizer himself offered it to her, and also paid up as the senior age category. I did not ask a friend about this, but a few weeks later I noticed one pattern, and then I got to it.

In general, in those days when this girl comes out, the performance of teenagers increases almost twice, and the team takes 40 minutes less time to work. Great, and most importantly, everyone is happy.