Question

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

Answer 1

Total ratio=9+11=20
number of girls=11/20*400
                          =220

Answer 2

Answer:  220

Step-by-step explanation:

Given : The ratio of boys to girls at a school is 9 to 11.

Let the number of boys be 9x and the number of girls be 11x.

Since there are 400 students attend the school.

Then we have the following equation :-

$9x+11x=400\\\\\Rightarrow\ 20x=400\\\\\Rightarrow\ x=\dfrac{400}{20}=20$

Now, the number of girls = 11x = 11(20)=220

Hence, there are 220 girls.