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Thread: Combinations

  1. #1
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    Combinations

    I'm stuck on this question:

    'In how many ways can a committee of 3 women and 4 girls be chosen from 7 women and 6 girls so that if the eldest woman is serving on the committee then the youngest girl is not?'

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    Senior Member integral95's Avatar
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    Re: Combinations

    So you first consider the case where the eldest women is chosen, that means there's 2 other women to choose from 6 and 4 girls from 5 since one of them is out.



    Then you consider the other case where the eldest women isn't chosen, that means there's 3 women from a group of 6 to choose from and a group of 4 girls from 6.



    Add them both to get 375, is that the answer?
    “Smart people learn from their mistakes. But the real sharp ones learn from the mistakes of others.”
    ― Brandon Mull

  3. #3
    Junior Member HeroWise's Avatar
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    Re: Combinations

    I second integral in this

  4. #4
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    Re: Combinations

    alternatively, divide into 3 cases:
    oldest woman in, youngest girl not
    oldest woman out, younger girl in
    oldest woman out, youngest girl out

    you get the same answer :-)
    just understand what you're doing and think your way through. integral's way is 100% correct too.

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