# Thread: Representing ratio in algebra

1. ## 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.

2. ## 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.

3. ## 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: . $\text{Total} \:=\:5n + 2n$