The school wants the ratio of girls to boys in…

The school wants the ratio of girls to boys in class IX to become 3 :

Question 13

MediumOriginal question

The table shows the number of boys and girls in five classes of a school in Guwahati.

Class	Boys	Girls
VI	45	55
VII	60	40
VIII	52	48
IX	72	50
X	63	57

The school wants the ratio of girls to boys in class IX to become $3 : 4$ by admitting only new girls. How many girls must it admit?

4Correct answerYour answer22Correct answerYour answer46Correct answerYour answer54Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer A

Correct answer: A

Class IX has 72 boys and 50 girls; the boys do not change.
Girls needed: $72 \times \frac{3}{4} = 54$ .
Girls to admit: $54 - 50 = 4$ .

Worth noting

54 is the number of girls class IX needs in all, not the number to admit. 46 reverses the ratio to $4 : 3$ , which would need 96 girls. 22 would make the girls equal to the boys.

Concept: Using a target ratio with one quantity fixed
Typical timeTypical: 80 s
Your timeYours: —

The rule this testsTables

Practise this chapter →

Ten questions from Data Interpretation, at your own pace.

Practise this chapter →

Ten questions from Data Interpretation, at your own pace.

The school wants the ratio of girls to boys in class IX to become 3 :

Question 13

Explanation