Tracey M. answered 06/27/18
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First I would change the ratios to fractions.
{When considering the ratio of boys to women is 2:1, add the two digits (2 + 1 = 3) and this will be your denominator. Now you have the fractions 2/3 for boys and 1/3 for women.}
Let X be the total number of people in the park.
We already know that 2/3 of the total people (X) are girls. That leaves 1/3·X to be the boys and women. Of that 1/3·X, 2/3 are boys and 1/3 are women (see above how to convert 2:1 to 2/3 and 1/3)
Now apply the fractions together:
Girls are 2/3·X
Boys are 1/3·X·2/3 = 2/9·X
Women are 1/3·X·1/3 = 1/9·X
Notice that the fractions total to 9/9·X or the entire number of people
We know that the number of girls is equal to the number of boys plus 12 so the equation becomes
2/3·X = 2/9·X +12
To clear the equation of fractions, multiply each term by 9
18/3·X = 18/9·X + 108
6X = 2X + 108
4X = 108
X = 27
The number of women is 1/9·X and that would be 1/9(27) = 3.