SOLUTION: In science class, there are 25% more girls than boys. If 3 girls leave, the number of boys is equal to the number of girls. How many total students are originally in class?

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Question 1050874: In science class, there are 25% more girls than boys. If 3 girls leave, the number of boys is equal to the number of girls. How many total students are originally in class?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
In science class,
let boys be b and girls g
if there are 25% more girls than boys, then we have:
since 25%=%2825%2F100%29=1%2F4, we have
g=b%2B%281%2F4%29b.....eq.1
if 3 girls leave , we have g-3
then the number of boys is equal to the number of girls:g-3=b......eq.2
from g-3=b......eq.2 we have g=b%2B3......eq.2a
since eq1 and eq2a have same left sides, equal right sides and solve for b

b%2B%281%2F4%29b=b%2B3....both sides multiply by 4
4b%2Bb=4b%2B12
4b%2Bb-4b=12
b=12
now find a
g=b%2B3......eq.2a
g=12%2B3
g=15
so, there is 15 girls and 12 boys