The whole point is that the rich kid is offering the reward solely if no other people choose the 6. NOT if its 10%. By choosing the 6, you necessarily lose the

The whole point is that the rich kid is offering the reward solely if no other people choose the 6. NOT if its 10%. By choosing the 6, you necessarily lose the money. Thus, you would only do that if the 6 points are more important to you than the reward, since you will absolutely lose the rich kid's reward if you choose it.