Consider the following distribution. | Class Interval | 0-20 | 20-40 | 40-60 | 60-80 | 80-100 | |---|---|---|---|---|---| | Frequency | 17 | 28 | 32 | f | 19 | f the mean of the above distribution is 50, find the value of f.

CUET UG 2025 — General Test Arithmetic

2025mcqmedium

Consider the following distribution.

Class Interval	0-20	20-40	40-60	60-80	80-100
Frequency	17	28	32	f	19

f the mean of the above distribution is 50, find the value of f.

Official previous-year question

Held on 15 May 2025 · Verified 13 Jul 2026.

Options

A
69
B
34
C
56
D
24

Did you get this right?

Solution

The class mark (midpoint) of each interval is the average of the lower and upper limits.

Class Interval	Class Mark (x)	Frequency (f)
0-20	10	17
20-40	30	28
40-60	50	32
60-80	70	f
80-100	90	19

The mean formula for grouped data is:

Mean $= \dfrac{\Sigma(f \times x)}{\Sigma f}$

Calculating $f \times x$ for each class:

Class Mark (x)	Frequency (f)	f × x
10	17	170
30	28	840
50	32	1,600
70	f	70f
90	19	1,710
Total	96 + f	4,320 + 70f

Given that the mean is 50:

$50 = \dfrac{4,320 + 70f}{96 + f}$

$50(96 + f) = 4,320 + 70f$

$4,800 + 50f = 4,320 + 70f$

$4,800 - 4,320 = 70f - 50f$

$480 = 20f$

$f = 24$

Therefore, the value of $f = 24$ .

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Class Interval

0-20

20-40

40-60

60-80

80-100

Frequency

Solution

The class mark (midpoint) of each interval is the average of the lower and upper limits.

Class Interval	Class Mark (x)	Frequency (f)
0-20	10	17
20-40	30	28
40-60	50	32
60-80	70	f
80-100	90	19

The mean formula for grouped data is:

Mean $= \dfrac{\Sigma(f \times x)}{\Sigma f}$

Calculating $f \times x$ for each class:

Class Mark (x)	Frequency (f)	f × x
10	17	170
30	28	840
50	32	1,600
70	f	70f
90	19	1,710
Total	96 + f	4,320 + 70f

Given that the mean is 50:

$50 = \dfrac{4,320 + 70f}{96 + f}$

$50(96 + f) = 4,320 + 70f$

$4,800 + 50f = 4,320 + 70f$

$4,800 - 4,320 = 70f - 50f$

$480 = 20f$

$f = 24$

Therefore, the value of $f = 24$ .

CUET UG 2025 — General Test Arithmetic

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CUET UG 2025 — General Test Arithmetic

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Solution

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CUET UG Arithmetic in other years

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Other General Test topics for CUET UG

General Knowledge

Logical Reasoning

Quantitative Reasoning

Geometry

Current Affairs

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