Monday, March 8, 2010

Monday Probability 9: Lizard in a Tetrahedron

A lizard is sitting at a vertex of a regular tetrahedron. At every move the lizard randomly selects one of the remaining vertices and moves to it. What is the probability that it will be back at the original vertex after n steps?

Answer: [1 - (-3)^(1-n)] /4

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