# 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:\(\begin{align}\text{Mean marks}=\frac{\text{Sum of marks}}{\text{Total no}\text{.of students}}\end{align}\)**

**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 \(73.\)