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

## 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: **

Mean marks

\[\begin{align}=\frac{\text{Sum of marks}}{\text{Total no}\text{.of students}}\end{align}\]

**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 \(= 85, 76, 90, 85, 39, 48, 56, 95, 81, 75\)

Mean marks

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

Thus, the mean marks obtained by a group of students are \(73.\)