SOLUTION: On the first day of school, the percentage of boys in a particular class is 60%. During the school year, six girls move away, and are replaced in the class by six boys; this makes

Algebra ->  Graphs -> SOLUTION: On the first day of school, the percentage of boys in a particular class is 60%. During the school year, six girls move away, and are replaced in the class by six boys; this makes      Log On


   

Question 143126: On the first day of school, the percentage of boys in a particular class is 60%. During the school year, six girls move away, and are replaced in the class by six boys; this makes the class roster 75% boys. Find the number of boys and girls in the class on the first day of school.
Answer by mangopeeler07(462) About Me  (Show Source):
You can put this solution on YOUR website!
first day of school boys=60%
midyear boys=75%
75-60=15

15% change from 6 boys, so
%286%2Fx%29=%2815%2F100%29

Cross multiply and get
600=15x

Divide and get
40=x

So there are 40 people in the class.

Now find 60% of 40, or 40(.6) and get 24. This is the number of boys. Subtract that from 40 and get 16. This is the number of girls.

Therefore, at the beginning of the school year, there were 24 boys and 16 girls.