NIACL Model Paper 7 with solutions for free online practice

Question : 63 of 100

Marks: +1, -0

The average weight of boys in a class is 48 kg and that of girls is 44 kg. If average weight of all the students of the class is 46.6 kg and the difference between number of boys and girls in the class is 24, what is the total number of students in the class ?

Validate

Solution:

(5) Number of boys = x
Number of girls = x - 24
According to the question,

48x + 44(x - 24) = (2x - 24) ×46.6

⇒

48x + 44x - 44 × 24

93.2x-24× 46.6

92x- 44 × 24 = 93.2x - 24 ×46.6

93.2× - 92 x = 24 (46.6 - 24)

1.2 x = 24 × 2.6

⇒x= {24 × 2.6}/1.2=52

∴ Total number of students = 2x - 24

= 2 × 52- 24 = 104 - 24 = 80

Go to Question:

Prev Question

Next Question