SOLUTION: In a school, there are 12% girls. If 5boys and 15girls are newly admitted to the school, the percentage of girls becomes 15. What is the total strength of the school? Z

Question 981206: In a school, there are 12% girls. If 5boys and 15girls are newly admitted to the school, the percentage of girls becomes 15. What is the total strength of the school? Z
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!
Before the additions, x girls, y boys.

The additions;

System of equations

Both of which have the term , making finding of x somewhat easy to do.

-----original count of the girls.
-

------original count of the boys.
Answer by MathTherapy(10552) (Show Source): You can put this solution on YOUR website!

In a school, there are 12% girls. If 5boys and 15girls are newly admitted to the school, the percentage of girls becomes 15. What is the total strength of the school? Z

Let number of students in school be S
If originally there were 12% girls, then original number of girls was: .12S
After addition of 15 girls, new number of girls = .12S + 15
New number of students: S + 5 + 15, or S + 20
Equation to form:
This translates to:
.15(S + 20) = .12S + 15 -------- Cross-multiplying
.15S + 3 = .12S + 15
.15S - .12S = 15 - 3
.03S = 12
S, or original number of students = , or
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