Question

the number of boys and girls in a class are in the ratio 7:5. The number of boys is 8 more than the number of girls. What is the total class strength.

Answer 1

given:

let the no. of girls be 5x and boys be 7x

the no. of of boys is 8 more than the no. of girls

so no. of boys = no. of girls + 8

> 7x = 5x +8

> 7x - 5x = 8

> 2x = 8

> x = 8/2

> x = 4

no. of boys = 7x = 7 ×4

= 28

no. of girls =5x = 5×4

= 20

so no. of boys is 28 and no. of girls is 20

Answer 2

Answer:

Step-by-step explanation:

Let,

Given,

number of boys in class = 7x

number of girls in class = 5x

So,

The total strength of class should be 7x + 5x  -- equation (i)

Again

The number of boys is 8 more than the number of girls or 7x = 5x + 8  -- equation (ii)

Then

Solving equation (i) & (ii)

⇒ 7x + 5x = 7x + 5x

⇒ 7x + 5x = (5x +8) + 5x            -- [putting the value of 7x from equation (ii) ]

⇒ 7x + 5x = 5x + 8 + 5x

⇒ 12x = 10x + 8

⇒ 12x - 10x = 8

⇒ 2x = 8

⇒ x = 8/2

⇒ x = 4

And now solving equation (i) to get total strength of class.

⇒  Total strength of class = 7x + 5x

⇒  Total strength of class = 7(4) + 5(4)

⇒  Total strength of class = 28 + 20

⇒  Total strength of class = 48

Hence, the total class strength is 48.