what fraction of the last sections students are girls?

Question

a school has six section per year level. three out of every seven ninth grade students are girls if each sections have 35 students and five of the six sections have a total of 76 girls what fraction of the last sections students are girls?

Answer 1

3 out of every 7 9th graders are girls so

Our ratio of girls to boys in 9th grade is 3:4 since for every 7 9th graders

we have 3 girls and 4 boys

 

(3/7)s = girls, where s = # 9th grade students

We have 6 sections of 35 students so:

s = 6(35) = 210 9th grade students

 

girls total = (3/7)(210) = 90

 

We have 76 of that total 90 in the 1st 5 sections leaving 90-76=14 girls in the 6th section,

out of a total of 35 students in the section.

The fraction of girls in the last section is 14 out of 35 = 14/35 = 2/5