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Math Help - Representing ratio in algebra

  1. #1
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    Representing ratio in algebra

    I have a problem where there are six more girls than boys and the ratio of girls to boys is 5:2.

    Now I can represent first statement as G = B + 6.

    But how do I represent the 5:2 ratio algebraically. This seems as if it should be very basic but can't seem to get my head around it.

    If total number of children had been mentioned I could have said total = 5G + 2B But I have no total. so how do I do it?

    I am most interested in how to represent the ratio 5:2 algebraically than an answer to the problem.
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  2. #2
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    Re: Representing ratio in algebra

    if the ratio of girls to boys is 5:2, then G = (5/2)B (that is, when B = 2, G = 5).

    that is, ratios are represented algebraically by fractions.
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  3. #3
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    Re: Representing ratio in algebra

    Hello, angypangy!

    There are six more girls than boys and the ratio of girls to boys is 5:2.

    Now I can represent first statement as G = B + 6.

    But how do I represent the 5:2 ratio algebraically?
    This seems as if it should be very basic, but can't seem to get my head around it.

    If total number of children had been mentioned,
    . . I could have said: total = 5G + 2B. . no
    But I have no total . . . so how do I do it?

    We are given: . G:B \,=\,5:2 . . . . which can be written: . \frac{G}{B} \,=\,\frac{5}{2}
    Substitute. G \,=\,B+6 .and get: . \frac{B+6}{B} \,=\,\frac{5}{2} \quad\hdots\text{ etc.}


    If we knew the total number of children,
    . . we could write: . \text{Total} \:=\:5n + 2n

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