# NCERT Solution class 7 chapter 3 exercise 3.1

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# Exercise 3.1

Question 1

Find the range of heights of any ten students of your class.

Sol :

Let the heights (in cm) of 10 students of our class be 125 , 127 , 132 , 133 , 134 , 136 , 138 , 141 , 144 , 146

Highest value among these observations = 146

Lowest value among these observations =125

Range = Highest value — Lowest value

= ( 146 – 125 ) cm
= 21 cm

Question 2

Organize the following marks in a class assessment, in a tabular form.

4 , 6 , 7 , 5 , 3 , 5 , 4 , 5 , 2 , 6 , 2 , 5 , 1 ,9 , 6 , 5 , 8 , 4 , 6 , 7

Sol :

 Marks Tally marks Frequency 1 | 2 || 3 | 4 ||| 5 6 7 8 9

(i) Which number is the highest?

Sol :

(ii) Which number is the lowest?

Sol :

(iii) What is the range of the data?

Sol :

(iv) Find the arithmetic mean.

Sol :