Question

In a park there are 28 girls. If the ratio of boys to girls is 6:7 how many boys are in the park?

Answer 1

24 boys.

Explanation:

The ratio of boys to girls in the park is 6:7. We can put this in a fraction format:

`(6)/(7)`

We can make a proportion:

`(6)/(7) =(b)/(28)` where b=number of boys

We can find what can be multiplied by 7 to get 28 or cross-multiply.

What can be multiplied by 7 to get 28? 4

Whatever we do to the denominator, we do to the numerator. 6•4=24

`(24)/(28)`

There are 24 boys in the park.

Cross-multiply:

When we cross-multiply, we multiply the first fraction's numerator with the second fraction's denominator and the first fraction's denominator with the second fraction's numerator.

`(6)/(7) =(b)/(28)` where b=number of boys

6•28=7•b

168=7b

`(168)/(7) =(7b)/(7)`

24=b

There are 24 boys in the park.