Question

present ages?
10. 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?
11. Bharat's father is 26 years younger than Bharat's ornndfath​

Answer 1

$\sf\large\underline{Given:}$

$\tt{\implies Ratio\:_{(boys\:and\: girls)}=7:5}$

$\tt{\implies Number\:_{(boys)}=Number\: girls\:_{(8\: more)}}$

$\sf\large\underline{To\: Find:}$

$\tt{\implies Total\:_{(class\: strength)}=?}$

$\sf\large\underline{Solution:}$

• Here, we can solve this question by equation method at first calculate the calculate the number of boys and girls than find their sum]

$\tt{\implies Let,\:the\: number\:of\:boys=x}$

$\tt{\implies Let,\:the\: number\:of\: girls=y}$

$\tt{\implies Boys\::\: girls=7:5}$

$\tt{\implies x:y=7:5}$

$\tt{\implies 5x=7y}$

$\tt{\implies x=\frac{7y}{5}-------(1)}$

$\tt{\implies Number\:_{(boys)}=Number\: girls\:_{(8\: more)}}$

$\tt{\implies x=y+8------(2)}$

• Putting the value of x here]

$\tt{\implies \dfrac{7y}{5}=y+8}$

$\tt{\implies 7y=5y+40}$

$\tt{\implies 7y-5y=8}$

$\tt{\implies 2y=40}$

$\tt{\implies y=20}$

• Now, putting value the y=20 in eq 2}[/tex]

$\tt{\implies x=y+8}$

$\tt{\implies x=20+8}$

$\tt{\implies x=28}$

$\sf\large{Hence,}$

$\tt{\implies Total\:_{(class\: strength)}=N\:_{(boys)}+N\:_{(girls)}}$

$\tt{\implies Total\:_{(class\: strength)}=28+20}$

$\tt{\implies Total\:_{(class\: strength)}=48}$

Answer 2

Given :

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

To Find :

• The total strength of the class.

Let us take the number of girls to be 5x

And Let us take the number of boys to be 7x.

The number of boys are 8 more than the number of girls,

⟹ 5x + 8 = 7x.

Solving this equation further,

⟹ 5x - 7x = -8

⟹ -2x = -8

$\sf{x = \frac{ - 8}{ - 2}}$

$\boxed{ \sf{ \pink{x = 4}}}$

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The number of girls in the class are 5x = 5 × 4 = 20.

The number of boys in the class are 7x = 7 × 4 = 28.

We are asked to find the strength of the class, i.e number of boys + number of girls.

Which is, 20 + 28 = 48.

Hence, the strength of the class is 48.

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