proportions, grade 9, question 13

29/11/2016 Grade 9 2,719

13) In a school, 70% of the students are boys.

Denote by x the total number of students and by y the number of girls.

  1. Express y interms of x.
  2. suppose that the school contains 200 students, find the number of girls.
  3. If the number of girls in this school is 75, find the total number of students.