Question

एक कॉलेज में लडके तथा लडकियों का अनुपात
3:2है। यदि 20% लड़के तथा 25% लड़कियाँ व्यरक है।
तो कितने प्रतिशत छात्र व्यरक नहीं है?​

Answer 1

AnswEr : [Eng. version]

78%

$\bf{\large{\green{\underline{\bf{Given\::}}}}}$

The boys and girls in a college are in the ratio 3:2. If 20% of the boys and 25% of the girls are adult.

$\bf{\large{\red{\underline{\bf{To\:find\::}}}}}$

The percentage of the student's who are not adult.

$\bf{\large{\green{\underline{\underline{\tt{Explanation\::}}}}}}$

Let the ratio be r

Assume, that 100 students in the class.

We have;

The ratio of boys = 3r

The ratio of girls = 2r

$\bf{\large{\underline{\underline{\tt{\red{A.T.Q.\::}}}}}}$

$\dashrightarrow\tt{3r+2r=100}\\\\\\\dashrightarrow\tt{5r=100}\\\\\\\dashrightarrow\tt{r\:=\:\cancel{\dfrac{100}{5} }}\\\\\\\dashrightarrow\tt{\green{r\:=\:20}}$

• Number of boy's = 3(20) = 60 Boy's.
• Number of girl's = 2(20) = 40 Girl's.

Now,

$\bf{\large{\green{\underline{\underline{\rm{The\:Number\:of\:boy's\:who\:are\:adults\::}}}}}}$

$\mapsto\tt{20\%\:of\:number\:boy's}\\\\\\\mapsto\tt{\dfrac{2\cancel{0}}{\cancel{100}} \times6\cancel{0}}\\\\\\\mapsto\tt{(2*6)}\\\\\\\mapsto\tt{\green{12\:boy's}}$

$\bf{\large{\green{\underline{\underline{\rm{The\:Number\:of\:girl's\:who\:are\:adults\::}}}}}}$

$\mapsto\tt{25\%\:of\:number\:girl's}\\\\\\\mapsto\tt{\dfrac{25}{10\cancel{0}} \times4\cancel{0}}\\\\\\\mapsto\tt{\cancel{\dfrac{100}{10}} }\\\\\\\mapsto\tt{\green{10\:girl's}}$

∴ Total number of boy's and girl's who are adult = (12+10) = 22 student's.

and;

Total number of boy's and girl's are not adult = (100 - 22) student's.

Total number of boy's and girl's are not adult = 78 student's.

$\bf{\large{\green{\underline{\underline{\rm{The\:percentage\:of\:the\:student's\:who\:are\:not\:adults\::}}}}}}$

$\longmapsto\tt{\bigg(\dfrac{Not\:adult\:student's}{Total\:student's} *100\bigg)\%}\\\\\\\\\longmapsto\tt{\bigg(\dfrac{78}{\cancel{100}} *\cancel{100}\bigg)\%}\\\\\\\\\longmapsto\tt{\green{78\:\%}}$

Thus,

The percentage of the student's who are not adult is 78% .

Answer 2

$\bf{\underline{\underline {English}}}$

$\bf{\red{\boxed{\boxed{Answer}}}}$

78% of the students in this college are not students.

$\boxed{\boxed{\bf{\green{Calculation}}}}}$

Total adult student = 20% of 3x + 25% of 2x

$= \frac{3x}{5} + \frac{2x}{4}$

$= \frac{12x +10x}{20}$

$= \frac{22x}{10}$

Total no of students who are adults :-

$= \frac{5x}{1} - \frac{22x}{20}$

$= \frac{100x - 22x}{20}$

$= \frac{78}{20}$

$= \frac{39x}{10}$

Required % = {39/10x/5x × 100%}

$= \frac{39}{50} \times 100$

=78%

Hence proved.

$\underline{\underline{\red{\bf{Hindi}}}}$

$\boxed{\boxed{\green{\bf{Answer}}}}$

इस कॉलेज में 78% प्रतिसत छात्र व्यरक नहीं है।

$\boxed{\boxed{\bf{\green{calculation}}}}}$

कुल वयस्क छात्र = 20% of 3x + 25% of 2x

$= \frac{3x}{5} + \frac{2x}{4}$

$= \frac{12x +10x}{20}$

$= \frac{22x}{10}$

कुल छात्रों की संख्या जो वयस्क हैं :-

$= \frac{5x}{1} - \frac{22x}{20}$

$= \frac{100x - 22x}{20}$

$= \frac{78}{20}$

$= \frac{39x}{10}$

अपेक्षित % = {39/10x/5x × 100%}

$= \frac{39}{50} \times 100$

=78%

इसलिए साबित हुआ।