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Counting Problem

  1. Oct 4, 2011 #1
    How many ways can you place 8 distinct flags on 3 distinct poles if no pole can be empty.


    Im not sure how to approach this problem because writing out all the possibilities would take a lot of time



    So I was thinking it would be something like

    8C3 to select the three flags that have to be placed.

    Then you could take any permutation of the flags on the poles to get 3!

    From there I was thinking that you could take the remaining flags and just place them on any of the poles

    This is what I got

    8C3 * 3!* 3^(5)

    I am not sure if it is right though
     
    Last edited: Oct 4, 2011
  2. jcsd
  3. Oct 4, 2011 #2
    clarify the problem

    "how many ways and you..."

    what does that mean?
     
  4. Oct 4, 2011 #3
    meant to same can you
     
  5. Oct 4, 2011 #4
    I think it's a combinatorics problem, it doesn't say how the poles are arranged.
     
  6. Oct 4, 2011 #5
    The poles dont move the flags on the poles move
     
  7. Oct 4, 2011 #6
    Oh sorry I was thinkig about a stand.

    In that case I think 8C3 isn't wrong.
     
  8. Oct 4, 2011 #7
    At least part of it is right...I just dont know how to verify it. I was thinking something with T numbers but I couldnt see how to work them in. So I just thought of what you could do.
     
  9. Oct 4, 2011 #8
    Here is how I think about it. If it removes the condition that it can have 2 flagged flags and one empty pole, then you gotta add more combinations.
     
  10. Oct 4, 2011 #9
    huh? what do you mean?
     
    Last edited: Oct 4, 2011
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