CentralNotice From Wikipedia, the free encyclopedia Jump to: navigation , search For other paradoxes by Joseph Bertrand, see Bertrand's paradox (disambiguation) . Bertrand's box paradox is a classic paradox of elementary probability theory . It was first posed by Joseph Bertrand in his Calcul des probabilités , published in 1889. There are three boxes: a box containing two gold coins, a box containing two silver coins, a box containing one gold coin and one silver coin. After choosing a box at random and withdrawing one coin at random, if that happens to be a gold coin, it may seem that the probability that the remaining coin is gold is 1 ⁄ 2 ; in fact, the probability is actually 2 ⁄ 3 . Two problems that are very similar are the Monty Hall problem and the Three Prisoners problem . These simple but counterintuitive puzzles are used as a standard example in teac...