SOLUTION: In a cafeteria, the ratio of the number of girls to the number of boys was 1:2. When 24 girls
entered the cafeteria, the new ratio of the number of girls to the number of boys be
Algebra.Com
Question 797438: In a cafeteria, the ratio of the number of girls to the number of boys was 1:2. When 24 girls
entered the cafeteria, the new ratio of the number of girls to the number of boys became 2:1.
How many pupils were in the auditorium at first?
Found 2 solutions by solver91311, stanbon:
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
There were 
girls and therefore 
boys. Then 24 girls came in, so there were 
and this number is 2 times the original number of boys, or 
Solve for , then calculate , then calculate 
John
Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
In a cafeteria, the ratio of the number of girls to the number of boys was 1:2.
Let k be the original # of students where x is the number of girls.
x + 2x = k
3x = k
x = k/3 (# of girls)
2x = (2/3)k (# of boys)
==============================
When 24 girls entered the cafeteria, the new ratio of the number of girls to the number of boys became 2:1.
-------
(k/3) + 24 = new # of girls
-----
(2/3)k is still the number of boys
--------
Equation:
[(k/3)+24] = 2[(2/3)k]
(k/3) + 24 = (4/3)k
k = 24
==============
How many pupils were in the auditorium at first?
Ans: k = 24
=================
Cheers,
Stan H.
=================
RELATED QUESTIONS
In the cafeteria, the ratio of the number of girls to boys is 6:7. When 117 girls enter... (answered by josmiceli)
girls are occupying exactly 2/5 of the sea in a cafeteria and boys I can find exactly 3/7 (answered by macston)
There are 50 boys and 60 girls in the cafeteria .After x boys and x-5 girls left the... (answered by robertb)
the number of boys is 2/7 of the number of girls. find the ratio of boys to girls. and... (answered by josmiceli)
in a club, the ratio of boys to girls is 7:8. the ratio of one less than the number of... (answered by mananth)
From a group of boys and girls, 14 girls leave first. Then the ratio of the number of... (answered by richwmiller)
From a group of boys and girls, 14 girls leave first. Then the ratio of the number of... (answered by ankor@dixie-net.com)
the ratio of the number of boys to the number of girls in a class was 2:3 at first. after (answered by robertb)
The ratio of the number of boys to the number of girls in a club was 9:8.
1/2 of the... (answered by stanbon)
