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Homework Help: Combinatorics problem - Permutations of ABDEFGH

  1. Mar 13, 2008 #1
    In theory I'm done this question, but would like to get it checked.

    22) How many permutations of the letters ABCDEFGH contain
    c) the strings BA and FGH?


    5 objects: BA, C, D, E, FGH.
    Total: 5! = 120

    This is following the example in the book. However, the example only has one cluster (Where a cluster is like BA, or FGH), and all of the book's clusters are in alphabetical order.

    For something like this, where we have two clusters, and it's BA, not AB, does my method still work?
  2. jcsd
  3. Mar 13, 2008 #2


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    That the order is alphabetical makes absolutely no difference. You knew that in your heart, right?
  4. Mar 13, 2008 #3
    That's what I figured, hence how I got my answer, but just wanted to check to be sure.
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