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Math Help - classifying a group in two different ways...

  1. #1
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    classifying a group in two different ways...

    ok in this problem i see the answer, im just not sure how my book came up with the 4/9 or where it came from?

    ok well let me post the problem....

    in a certain reading group organized of only senior and junior students, 3/5 of the students are boys, and the ratio of seniors to juniors is 4:5. if 2/3 of girls are seniors, what fraction of the boys are juniors?

    the answer in the book is 19/27

    what the author did was create a table, at the bottom of his table he has A+B=4/9

    where A = senior boys and B=senior girls, my question is where did the 4/9 come from?
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  2. #2
    Super Member ILikeSerena's Avatar
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    Re: classifying a group in two different ways...

    Hi slapmaxwell1!

    It comes from the statement: the ratio of seniors to juniors is 4:5.

    It means that in every 9 students, 4 are seniors and 5 are juniors.
    So 4/9 of the students are senior.
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  3. #3
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    Re: classifying a group in two different ways...

    thx now i can finish my table and solve it!
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