Question

Example 6. In class VIII of a school, girls are 60% of the total number of students. If there are
18 girls in class, find the total number of students and number of boys in the class.
Solution. Let the total number of students be x.​

Answer 1

Answer:

• Number of boys = 12
• Total number of students = 30

GivEn:-

• Girls are 60% of the total number of students.
• The number of girls is 18

To Find:-

• The number of boys
• Total number of students

Step-by-step explanation:

Let the total number of students be x

Therefore, the number of boys is ( x - 18 )

Now, according to the question,

$\implies \sf \: x \times \dfrac{60}{100} = 18$

$\implies \sf \: x = 18 \times \dfrac{100}{60}$

$\implies \sf \: x = 18 \times \dfrac{10}{6}$

$\implies \sf \: x = 3\times 10$

$\boxed{ \pink{ \sf{ \implies \: x = 30}}}$

Therefore, the total number of students is 30

And number of boys is ( 30 - 18 ) = 12

Answer 2

Question

In class VIII of a school, girls are 60% of the total number of students. If there are

18 girls in class, find the total number of students and number of boys in the class.

Solution. Let the total number of students be x.

Solution

Let, the total number of students be x

Girls are = 60x/100

ATP

$\frac{60x}{100} = 18 \\ = ) \: 60x = 18 \times 100 \\ = ) \: x = \frac{1800}{60} = 30$

Number of girls

$= \frac{60}{100} \times 30 \\ = 18$

Number of boys = (30-18) = 12

Ans:- The total number of students is 60.

The number of boys is 12.

The number of girls is 18.

Learn More

Remember this formula:-

$percentage \: increase \: \\ = ( \frac{increase \: in \: value}{original \: value})$

$percentage \: decrease \\ = ( \frac{decrease \: in \: value}{original \: value})$