# ratio, rate and proportion

In a club there are 1500 boys and some girls, the ratio of number of girls to the boys is 3:10. after some more girls joined the club, the ratio of number of girls to the number of boys becomes 9:15. Find the innitial number of girls in the club.

• If you have 1500 boys and some girls and a ratio of girls to the boys of 3:10. Then the initial number of girls is simply $$\frac{1500*3}{10}=450$$ – Dr. Mathva Nov 26 '18 at 19:53

If there are 3 girls for every 10 boys let $$B=10x=1500$$ so $$x=150$$. Thus $$G=3x=450$$. The second part is not needed to find the initial number of girls but it is a similar problem. If the new ratio is $$9:15$$, then $$B=15y=1500$$ and $$y=100$$ so $$G=9x=900$$ meaning that the girl population has doubled.