Maths
posted by Javier .
There were 40 members in a hockey club. 3/8 of them were girls. When more girls joined the club, the percentage of the number of girls increased to 75%. How many more girls had joined the club?
Some teachers attended a workshop. They were divided into Group X and Y. The ratio of the number of teachers in Group X to the number of teachers in Group Y was 2:3. All the teachers in Group X were women. The ratio of the number of women in Group Y to the number of men in Group Y was 2:7. What fraction of the teachers who attended the workshop were men?

3/8 of 40 = 15 girls
(15+x)/(40+x) = 3/4, so x = 60
check: 75/100 = 3/4

men fraction = (7/9 y)/(x+y)
but, x/y = 2/3, so x=2y/3
so, men fraction = (7y/9)/(2y/3 + y) = (7y/9)/(5y/3) = 7/15