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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A particle is bouncing randomly in a two-dimensional box. How far does it travel between bounces, on average? Suppose the particle is initially at some random position in the box and is traveling in a straight line in a random direction and rebounds normally at the edges.
Solution
