10 Students of Class X took part in a Mathematics quiz. if the number of girls is 4 more than the number of boys.

Q(1). 10 students of class X take 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. 

Solution:

We do not know how many girls and how many boys

Let be girls = X

Let be boys = Y

In question 10 number of students in class given 

That means number of girls + boys = 10

    X + Y = 10 ---------------(1)

Number of girls is 4 more than the number of boys

    X=Y+4

Now form the equation type

Bring the Y this side of equal it will be –Y

   X – Y = 4 ----------------(2)

Now take equation (1)

X + Y = 10

Move X that side of equal it will be –Y

   Y = 10 – X

We do not know what x values to take, do not confuse

You can take x value from 1 and substitute in y equation form

   Y=10-X

   Y=10-1=9 

   Y=10-2=8

   Y=10-3=7

 Now make table

 

   

Now take equation (2) 

    X-Y=4

 Move y that side of equal and 4 move this side it will be -4

    X-4=Y or we can also write 

    Y=X-4

 You can take x value from 1 and substitute in y equation form

 Y=X-4

 Y=1-4=-3

 Y=2-4=-2

 Y=3-4=-1

 Now make table

 

 Now plot the points on the Graph page.

Intersect point is (x,y)=(3,7)

Number of girls (x) = 7

Number of boys (y) = 3