MBApyq

Number of Girls in Class

MAT 2018 · Mathematical Skills · Easy · Averages

All MAT 2018 questionsMore Averages questionsAll MAT MS

The average age of boys and girls in a class is 10.5 years; that of the boys is 10.6 years and that of the girls is 10.1 years. If there are 60 boys in the class, how many girls are there in the class?

  1. A.

    15

  2. B.

    20

  3. C.

    22

  4. D.

    25

Answer

A

Explanation

Using Alligation: Boy's avg = 10.6, Girl's avg = 10.1, Total avg = 10.5. Ratio of Boys : Girls = (10.5−10.1):(10.6−10.5)=0.4:0.1=4:1(10.5 - 10.1) : (10.6 - 10.5) = 0.4 : 0.1 = 4 : 1. Given Boys = 60 ⇒4x=60⇒x=15\Rightarrow 4x = 60 \Rightarrow x = 15. Number of girls = 15.

Related Averages questions

Practise this under exam conditions

Sign in to solve it with a live timer, the on-screen CAT calculator, and streak and accuracy tracking across every question you attempt.

Solve in the workspace