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Homework Help: Short Probability (permutation) question

  1. May 11, 2010 #1
    1. The problem statement, all variables and given/known data

    There is a total of 19 students sitting in a semi-cirlce. How many seating arrangements are possible, if 4 of the 19 students have to sit next to each other?

    3. The attempt at a solution

    I'm not sure if the calculation is:

    15! x 4!


    19! / 4!

  2. jcsd
  3. May 11, 2010 #2


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    Science Advisor
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    Gold Member

    I would go with the first answer, assuming you can explain it. :smile:
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