(i) 10 students of Class X took part in a Mathematics quiz. If the number of girls is 4 more than the number of boys, find the number of boys and girls who took part in the quiz.

EXERCISE 3.2

1. Form the pair of linear equations in the following problems, and find their solutions graphically.

(i) 10 students of Class X took part in a Mathematics quiz. If the number of girls is 4 more than the number of boys, find the number of boys and girls who took part in the quiz.

Let number of boys = x

Number of girls        = y

Given that total number of student  is 10 so that

x + y    = 10

Subtract y both side we get

x          = 10 – y

Plug y = 0 , 5, 10 we get

x         = 10 – 0          = 10

x         = 10 – 5          = 5

x         = 10 – 10        = 0

X	10	5
Y	0	5

Given that If the number of girls is 4 more than the number of boys

So that

y          =  x + 4

Plug x = -4, 0, 4, and we get

Y         =  - 4 + 4         = 0

Y         =  0 + 4           = 4

Y         =  4 + 4           = 8

X	-4	0	4
y	0	4	8

So number of boys = 3 and number of girls = 7