# Ex.3.1 Q6 Data Handling - NCERT Maths Class 7

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## Question

The marks (Out of $$100$$) obtained by a group of students in a science test are
$$85, 76, 90, 85, 39, 48, 56, 95, 81, 75.$$ Find the: -

(i) Highest and lowest marks obtained by the students.

(ii) Range of the marks obtained.

(iii) Mean marks obtained by the group.

## Text Solution

What is known?

Marks obtained by a group of students in a science test.

What is unknown?

Highest and lowest marks, Range of the marks, Mean marks

Reasoning:\begin{align}\text{Mean marks}=\frac{\text{Sum of marks}}{\text{Total no}\text{.of students}}\end{align}

Solution:

(i) Highest marks obtained by the student $$= 95$$
Lowest marks obtained by the student $$= 39$$

(ii) Range of the marks = Highest marks – Lowest marks
$$= 95 – 39$$
$$= 56$$

Total no. of students $$= 10$$

Marks obtained by the group of students $$= 85, 76, 90, 85, 39, 48, 56, 95, 81, 75$$

\begin{align}{\text{Mean marks}} &=\frac{{{\text{Sum of marks}}}}{{{\text{Total no}}{\text{.of students}}}}\\ &= \frac{{85 + 76 + 90 + 85 + 39 + 48 + 56 + 95 + 81 + 75}}{{10}}\\ &= \frac{{730}}{{10}}\\ &= 73\end{align}

Thus, the mean marks obtained by a group of students are $$73.$$

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