The forestry high school has 900 students. The ratio of the number of girls to the number of boys is 5:4.

a) How many girls and how many boys attend this school?

b) In an average class, there are 27 students. If this class is representative of all students in the school, how many students in this class are girls? How many students are boys?

number of girls --- 5x

number of boys --- 4x

5x+4x=900
x=100
so 500 girls and 400 boys

5/9 of the 27 students in the class would be girls
so what is (5/9)(27) ?