Question

Half of the number of boys of Class 8 B went to the football ground to play. One-fourth of the number of boys went to the Library to take books. Remaining 10 boys went to the 3rd Language room. Find the number of boys of Class 8 B.

Answer 1

Let the total number of boys be x

Boys who went to play

= \frac{1}{2} x = \frac{x}{2}=

2

1

x=

2

x

Who went to library

= \frac{1}{4} x = \frac{x}{4}=

4

1

x=

4

x

Boys who went to the third language room =10

So, the equation can be formed as,

\frac{x}{2} + \frac{x}{4} + 10 = x

2

x

+

4

x

+10=x

\frac{x}{2} + \frac{x}{4} - x = - 10

2

x

+

4

x

−x=−10

\frac{2x + x - 4x}{4} = - 10

4

2x+x−4x

=−10

\frac{ - x}{4} = - 10

4

−x

=−10

cancelling the - sign , we have

\frac{x}{4} = 10

4

x

=10

x = 10 \times 4x=10×4

x = 40

So,

the number of boys in class 8B are 40