I have said elsewhere that wagering is a way to operationally define how certain you are. As the bet gets higher and higher, the certainty gets greater and greater. But it should always be kept in mind that "certainty" is not in the outside world, it's in your head. Consider the puzzle below from Marilyn Vos Savant. One reader was willing to bet a million dollars that he was right. Do you think you could come up with an answer that you would bet a million dollars on?
Two men drive for 100 miles. The speed limit for the first 50 miles is 55 mph; for the second 50 miles, it is 65 mph. One man stops for gas duing the first half; the other stops during the second half. Both stops take 15 minutes. Who will finish first?
Can you solve this puzzle with high confidence (say a bet of $100) with a simple solution?