LIC AAO Model Paper 1

Question : 38 of 160

Marks: +1, -0

Each boy contributed rupees equal to the number of girls and each girl contributed rupees equal to the number of boys in a class of 60 students. If the total amount thus collected is Rs. 1600, how many boys are there in the class?

30
25
50
Data Inadequate
None of these

Validate

Solution:

If the number of boys = x
then number of girls = 60 - x
∴ (60 - x) x + (60 - x)x = 1600
⇒ 2(60x-

x^2

) = 1600
⇒

x^2

-60x+800 = 0
⇒

x^2

-40x-20x + 800 = 0
⇒ x (x- 40) - 20 (x- 40) = 0
⇒ (x- 20) (x- 40) = 0
⇒ x= 20 or 40

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