Question

A class has three fewer girls than boys. If the ratio of girls to boys is four to five, how many students are there in the class?

Answer 1

27

Explanation:

Girls = boys - 3

girls / boys = 4/5

Substitute (boys - 3) in for girls

boys - 3 / boys = 4/5 Cross multiply

5(boys - 3) = 4* boys Remove the brackets

5boys - 15 = 4boys Subtract 5 boys from both sides.

-5boys -5boys

- 15 = - boys Multiply both sides by - 1

15 = boys

Girls = boys - 3

girls = 15 - 3

girls = 12

Total 15 + 12

total = 27