How I Plan to Make Some Easy Money

Jorge Stolfi
February 17, 2014

Method A

I ask a guy to show me a 50 dollar bill. I grab the bill and run.

Evaluation of Method A

Advantages:I make 50 dollars.
Disadvantages:Victim shouts "thief", calls police, they get me and I go to jail.

Not good. Forget Method A.

Method B

I ask ten people to form a circle, each holding a 50 dollar bill. I tell each person to pass his bill to the next guy at his right, slowly at first but gradually quickening.

I show them mathematically that, at any moment, the sum that each one had, plus everything that he received from his Left neighbor, is always more than what he gave to his Right neighbor; so that everybody will win in the end.

I give the example by taking the bill from my Left neighbor and giving it to my Right neighbor, "like this, see." Soon the eleven of us are smoothly passing the ten bills around.

A passer-by asks, "may I join too?" "Sure, get a 50 dollar bill and enter the circle." "If I contribute two bills, will I get twice the profit?" "Of course!" He calls two of his friends, who call others, and so on.

Soon we are twenty-one people circulating thirty bills. Everybody notices that the method is working: each one now must grab another bill from Left before he has a chance to give his bill to Right.

A few minutes later, I stop for a moment to pick up the pen that I dropped on the floor. While doing so I discreetly pocket the bill that Left just handed me, and I immediately resume the play. With the bills in motion, no one can count them and notice that now there are only twenty nine going around.

No, wait, that guy across the circle is angrily staring at my pocket, he noticed my trick! I am done! But, instead of blowing the whistle, the scoundrel winks at me, pauses for a moment to blow his nose, discreetly pockets the bill from Left too, and goes on playing. Phew!

But I'd better play safe. I tell everybody, "sorry folks, I must pick up my turtle at the gym, you carry on without me." And I walk out holding high "my" bill, that I just got from Left. That scoundrel does the same. The other nineteeen guys thank me for the great opportunity and keep on passing the remaining twenty-six bills around, already thinking on how they will spend their profit.

Evaluation of Method B

Advantages: I make 100 dollars.
Disadvantages: I don't know yet, let's see how that Bitcoin thing ends.


Last edited on 2014-02-17 17:32:13 by stolfi