TYI 30 asked Elchanan Mossel’s Amazing Dice Paradox (that I heard from Yuval Peres yesterday)
You throw a die until you get 6. What is the expected number of throws (including the throw giving 6) conditioned on the event that all throws gave even numbers?
Most people answered 3.
Is it the right answer?
Please use now the comments thread to offer your answers, explanations, insights, intuition, thoughts and after-thoughts. I am especially eager to hear your take, James Martin! For a nice explanation by Paul Cuffis, see this comment by Yuval.
Comments on the English dilemma between “a die” or “a dice” are also welcome.
(Let me also draw your attention to TYI 29 about exciting models of random trees.)