3/7 of a class are boys. What fraction of the class consists of girls if there are 28 girls, how many boys are there in the class.

Answer 1

No response

Answer 2

Fraction of girls:

1 - 3 / 7 = 7 / 7 - 3 / 7 = 4 / 7

x = numbers of sudents

there are 28 girls

4 / 7 x = 28

Multiply both sides by 7

4 x = 196

x = 196 / 4 = 49

49 students there in the class.

3 / 7 of 49 are boys

3 • 49 / 7 = 21 boys

OR

boys / girls = 3 / 4

3 • 28 / 4 = 21 boys