The ratio of boys to girls at a school is 9 to 11. if 400 students attend the school, how many are girls?

In 400 students, the girls will be 220 since the ratio of boys to girls is 9:11. The boys will be equal to 180.

Solution:

9x + 11x = 400
20x = 400
x = 20

To get the ratio:

9 * 20 = 180 boys
11 * 20 = 220 girls

A ratio is simply a comparison between two numbers. To keep it simple, we'll ignore the units (e.g., cost in dollars or weight in ounces) and focus just on the number part for a bit. For example, how does 3 compare to 6? Well, three is half of six. We can write ratios in one of three ways:

3 : 6
3 / 6
3 to 6

Practice solving ratio word problems at Khanacademy.org.

Tag: girls 
Friday, June 23 2017
Source: https://www.algebra.com/algebra/homework/Percentage-and-ratio-word-problems/Percentage-and-ratio-word-problems.faq.question.234606.html