I’ve enjoyed several books by and about Lewis Carroll with puzzles, games and neat observations. I’m going to post a few here. Here’s a simple one with which to get started.
Suppose that I secretly flip a coin and place either a blank or white stone in a bag based on the result. I then put a white stone in the bag for two stones in total. I invite you to pull one stone out and it turns out that it is white. What is the chance that the other stone in the bag is also white?