Question

Tania knows that the ratio of boys to girls in her class is 3:5. Since 20 of the students are girls, she says that there must be 30 students in her class. Is she right? Explain your thinking.

Answer 1

Answer: 32 students in the classroom

Explanation:

Let the no. of students be x, so

3/8x + 20 = x

3/8x - x = -20

-5/8x = -20

Multiply both sides by -8/5,

x = 32

Answer 2

No, there are 32 students in her class.

Explanation:

The ratio to boys and girls is

`3:5`

There are 20 girls in the classroom.

`20/5=4`

`3 * 4= 12`

`5 * 4 =20`

`12:20`

`12+20=32`