The class marks of a frequency distribution are given as follows :
15, 20, 25, ...
The class corresponding to the class mark 20 is:
a. 12.5 - 17.5
b. 17.5 - 22.5
c. 18.5 - 21.5
d. 19.5 - 20.5

Solution:

We know that

Width = 5

Class marks = 20

We can calculate

Lower limit = 20 - 5/2

= (40 - 5)/2

= 35/2

= 17.5

In the same way

Upper limit = 20 + 5/2

= (40 + 5)/2

= 45/2

= 22.5

Therefore, the class corresponding to the class mark 20 is 17.5 - 22.5.

✦ Try This: The class marks of a frequency distribution are given as follows : 10, 20, 30, ... The class corresponding to the class mark 15 is :
a. 12.5 - 17.5
b. 17.5 - 22.5
c. 18.5 - 21.5
d. 19.5 - 20.5

☛ Also Check: NCERT Solutions for Class 9 Maths Chapter 14

NCERT Exemplar Class 9 Maths Exercise 14.1 Problem 6

The class marks of a frequency distribution are given as follows : 15, 20, 25, ...The class corresponding to the class mark 20 is : a. 12.5 - 17.5, b. 17.5 - 22.5, c. 18.5 - 21.5, d. 19.5 - 20.5

Summary:

The class marks of a frequency distribution are given as follows : 15, 20, 25, ... The class corresponding to the class mark 20 is 17.5 - 22.5

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