Usenet Newsgroups : rec.puzzles Hall of FameThe rec.puzzles Hall of Fame is a compilation of over 500 of the most popular puzzles that have been posted and discussed in the rec.puzzles newsgroup. In most cases a detailed solution has been provided. Many of these puzzles also appear in Braingle's own collection. |
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One urn contains black marbles, and the other contains white or black marbles with even odds. You pick a marble from an urn; it is black; you put it back; what are the odds that you will draw a black marble on the next draw? What are the odds after n black draws?
Solution
