# Ex.8.1 Q3 Comparing Quantities - NCERT Maths Class 8

Go back to  'Ex.8.1'

## Question

$$72\%$$ of $$25$$ students are interested in mathematics. How many are not interested in mathematics?

Video Solution
Comparing Quantities
Ex 8.1 | Question 3

## Text Solution

What is known?

Total number of students $$= 25$$

Percentage of students who are interested in Mathematics $$= 72\%$$

What is unknown?

Number of students who are not interested in Mathematics

Reasoning:

Percentage is a special ratio that compares any quantity to $$100,$$ with $$100$$ representing one whole.

Steps:

Percentage of students who are not interested in Mathematics

\begin{align}& = \left( {100-72} \right)\%\\&= 28\% \end{align}

Therefore, number of students who are not good in Mathematics

\begin{align}&= 28\%\,\text{of the total number of students}\\&= 28\% \,\text{of} \,25 \\&= \frac{{{28}}}{{{100}}}{ \times 25}\\&=\frac{{{28}}}{{4}}\\& = 7\end{align}

The total number of students who are not interested in Mathematics are $$7.$$

Learn from the best math teachers and top your exams

• Live one on one classroom and doubt clearing
• Practice worksheets in and after class for conceptual clarity
• Personalized curriculum to keep up with school