Question

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

Answer 1

Let number of boys = x
Number of girls = y
Given that total number of student is 10.
So, x + y = 10
Subtract y both side we get,
x = 10 – y
Putting y = 0 , 5, 10 we get,
x = 10 – 0 = 10
x = 10 – 5 = 5
x = 10 – 10 = 0
$\begin{array}{cccc}x& 10& 5& 0\\ y& 0& 5& 10\end{array}$
Given that If the number of girls is 4 more than the number of boys.
So, y = x + 4
Putting x = -4, 0, 4, and we get,
y = - 4 + 4 = 0
y = 0 + 4 = 4
y = 4 + 4 = 8
$\begin{array}{cccc}x& -4& 0& 4\\ y& 0& 4& 8\end{array}$
Graphical representation:

Therefore, number of boys = 3 and number of girls = 7