Question

the no. of boys and girls in a class are in a ratio of 7:5 .the no. of boys is 8 more than the no. of girls what is the total class strength​

Answer 1

It is given that the ratio of number of boys to the number of girls is 7 : 5. It means :

• ( Number of boys ) : ( Number of girls ) = 7 : 5

Let the number of boys be 7a and number of girls be 5a.

Also, given, number of boys is 8 more than the number of girls, it simply means that if the number of girls is 5a, then the number of boys will be 5a + 8 .

According to this question : -

= > Number of boys = number of girls + 8

= > 7a = 5a + 8

= > 7a - 5a = 8

= > 2a = 8

= > a = 4

Hence, required number of boys is 7a i.e. 7( 4 )i.e. 28 and number of girls is 5a i.e. 5( 4 ) = 20.

Therefore,

= > Total strength of the class = number of boys + number of girls

= > Total strength of the class = 28 + 20 = 48

Hence the required strength of the class is 48.

Answer 2

Let the number of boys be 7x and girls be 5x.

According to the question,

7x = 5x + 8

⇒ 7x – 5x = 8

⇒ 2x = 8

⇒ x = 8/2

⇒ x = 4

Therefore, Number of boys = 7×4 = 28

And, Number of girls = 5×4 = 20

Total number of students = 20+28 = 48