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Homework Help: Probability: Circular Tables

  1. Aug 29, 2010 #1


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    Gold Member

    1. The problem statement, all variables and given/known data

    How many unique ways are there to arrange 5 people around a circular table?

    2. Relevant equations


    3. The attempt at a solution

    This should be a pretty simple question, but I can't seem to focus on much of anything now, so I'm really not confident in my solution. I figured that if it were a straight line or something like that, then there would be 5! unique ways of arranging the people. However, since this is a round table, I guessed that ways of arranging individuals which were merely a rotation from another orientation shouldn't be counted more than once. Since there were five corners per se, I figured that only 1/5 of the original 5! ways of arranging people were actually unique; and thus, there would be 4! unique ways of arranging 5 people around a circular table.

    I know that this reasoning isn't rigorous by any stretch of the imagination, but I was wondering if it is even correct (or if the answer is close to correct). Thanks for any feedback.
  2. jcsd
  3. Aug 29, 2010 #2
    think about how 5 people sit in a row. in circular shape, we can't exactly know the start point. So we Freeze one person and all other 4 people rotates, so you are actually in a right directions
    Last edited: Aug 29, 2010
  4. Aug 30, 2010 #3


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    Yes, you can seat one person anywhere on the table, leaving the other 4 to be seated as if that person were one end of a straight table. 4! is the correct ansswer.
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