Probability 101 in New Logic/Math Puzzles Posted July 2 · Report reply @EventHorizon said, But once Plato says that "one die is a 4," it doesn't merely prune out the ones without 4's. That’s the crux of it. EH is correct that this reads on Monty Hall. But more directly on the long-running Teanchy-Beanchy post (one of his two kids is a girl, what’s the probability he has two girls.) First people said has to be 1/2. Then others (including me) said (all that matters is that) it can’t be BB so it’s 1/3. Both wrong. so I made this one up to show that the informant’s algorithm has to be known. Nicely explained.