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Homework Help: Combinations for word parallelogram

  1. Apr 5, 2004 #1
    How many ways can you select four letters out of the word parallelogram ?

    The answer on the book is 150. For me im stuck at using 8C4 and it seems to be the logical way. The reason I chose 8 is because some letters are repeating. So how can they have 150?
  2. jcsd
  3. Apr 5, 2004 #2
    4 letters or 4 different letters?

  4. Apr 5, 2004 #3
    It just says four letters, not four different letters
  5. Apr 5, 2004 #4
    You can't just remove those letters since you can have a combo of aaap and aapl and aplo. Eliminating those letters will eliminate alot of your combinations.
  6. Apr 6, 2004 #5
    I see, but 13C4 is quite big relative to 150 and I see no way how its 150
  7. Apr 6, 2004 #6


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    Staff Emeritus
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    Well, one thing is that para and para, while different selections, constitute the same 4 letters, I suppose, so shouldn't both be counted. The question as stated is vague on this point!
  8. Apr 6, 2004 #7
    The original question from the text is as follows:

    "Determine the number of ways of selecting, without regard to order, from the word parallelogram"
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