Check out my books on Amazon (paid link): https://amzn.to/2SiQjlp I have two envelopes, one with $100 and one with nothing. You can choose one. But before you do, I will offer you a little more information. I have a canister with five balls in it, three marked with the correct envelope and two marked with the wrong envelope. How much would you be willing to pay to look at one of the balls? And how much more would you be willing to pay to look at a second? The first question is pretty straightforward. The second one is deceptive. Be careful!