Find the odd man out 1, 4, 9, 16, 20, 36, 49

Option c: 20. Solution: Let's check the perfect square property for each number in the series: - 1 = 12 - 4 = 22 - 9 = 32 - 16 = 42 - 36 = 62 - 49 = 72 - 20 is not a perfect square ( 42 = 16 and 52 = 25 ). Since 20 is the only number in the series that is not a perfect square, it is the odd man out. Hence, Option C is the correct answer.

Find the odd man out $1, 4, 9, 16, 20, 36, 49$

The correct answer is Option c: $20$. Let's check the perfect square property for each number in the series: - $1 = 1^2$ - $4 = 2^2$ - $9 = 3^2$ - $16 = 4^2$ - $36 = 6^2$ - $49 = 7^2$ - $20$ is not a perfect square ($4^2 = 16$ and $5^2 = 25$). Since $20$ is the only number in the series that is not a perfect square, it is the odd man out. Hence, **Option C** is the correct answer.

Number Series, Coding and DecodingMCQMTP May 18Question 2175 of 217

All Questions

Find the odd man out $\displaystyle 1, 4, 9, 16, 20, 36, 49$

Options

\displaystyle 1

\displaystyle 9

\displaystyle 20

\displaystyle 36

For any discrepancies in this question, email contact@cadada.in

Correct Answer

✅ Option c — $\displaystyle 20$

All Options:

A $\displaystyle 1$
B $\displaystyle 9$
C $\displaystyle 20$
D $\displaystyle 36$

Detailed Solution & Explanation

Let's check the perfect square property for each number in the series:
-

\displaystyle 1 = 1^2

\displaystyle 4 = 2^2

\displaystyle 9 = 3^2

\displaystyle 16 = 4^2

\displaystyle 36 = 6^2

\displaystyle 49 = 7^2

\displaystyle 20

is not a perfect square (

\displaystyle 4^2 = 16

and

\displaystyle 5^2 = 25

).

Since

\displaystyle 20

is the only number in the series that is not a perfect square, it is the odd man out.

Hence, **Option C** is the correct answer.

About This Chapter: Number Series, Coding and Decoding

Paper

Paper 3: Quantitative Aptitude

Weightage

5 Marks

Key Topics

Number series, Coding & Decoding, Odd man out

This chapter covers Number series, Coding & Decoding, Odd man out and is part of Paper 3: Quantitative Aptitude in the CA Foundation exam.

View Official ICAI Syllabus

Exam Strategy Tip

This topic carries 5 Marks weightage. Focus on understanding core concepts rather than memorizing.

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Find the odd man out 1,4,9,16,20,36,49\displaystyle 1, 4, 9, 16, 20, 36, 491,4,9,16,20,36,49