Find the odd man out from the following series : 7, 23, 47, 119, 171, 287 .

Option a: 171. Solution: Let's examine the mathematical pattern of the terms in the series: 7, 23, 47, 119, 171, 287 . Each correct term follows the pattern p2 - 2 , where p is a consecutive prime number starting from 3 : - For p = 3 : 32 - 2 = 7 - For p = 5 : 52 - 2 = 23 - For p = 7 : 72 - 2 = 47 - For p = 11 : 112 - 2 = 119 - For p = 13 : 132 - 2 = 167 (the series lists 171 , which is incorrect) - For p = 17 : 172 - 2 = 287 The pattern of p2 - 2 using consecutive prime numbers holds perfectly for all terms except 171 , which should be 167 . Therefore, 171 is the odd man out. Hence, Option A is the correct answer.

Find the odd man out from the following series : $7, 23, 47, 119, 171, 287$.

The correct answer is Option a: 171. Let's examine the mathematical pattern of the terms in the series: $7, 23, 47, 119, 171, 287$. Each correct term follows the pattern $p^2 - 2$, where $p$ is a consecutive prime number starting from $3$: - For $p = 3$: $3^2 - 2 = 7$ - For $p = 5$: $5^2 - 2 = 23$ - For $p = 7$: $7^2 - 2 = 47$ - For $p = 11$: $11^2 - 2 = 119$ - For $p = 13$: $13^2 - 2 = 167$ (the series lists $171$, which is incorrect) - For $p = 17$: $17^2 - 2 = 287$ The pattern of $p^2 - 2$ using consecutive prime numbers holds perfectly for all terms except $171$, which should be $167$. Therefore, $171$ is the odd man out. Hence, **Option A** is the correct answer.

Number Series, Coding and DecodingMCQPYQ Sep 24Question 2174 of 217

All Questions

Find the odd man out from the following series : $\displaystyle 7, 23, 47, 119, 171, 287$ .

Options

A171

B119

C287

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

Correct Answer

✅ Option a — 171

All Options:

A171
B119
C287
D7

Detailed Solution & Explanation

Let's examine the mathematical pattern of the terms in the series:

\displaystyle 7, 23, 47, 119, 171, 287

.
Each correct term follows the pattern

\displaystyle p^2 - 2

, where

\displaystyle p

is a consecutive prime number starting from

\displaystyle 3

:
- For

\displaystyle p = 3

\displaystyle 3^2 - 2 = 7

- For

\displaystyle p = 5

\displaystyle 5^2 - 2 = 23

- For

\displaystyle p = 7

\displaystyle 7^2 - 2 = 47

- For

\displaystyle p = 11

\displaystyle 11^2 - 2 = 119

- For

\displaystyle p = 13

\displaystyle 13^2 - 2 = 167

(the series lists

\displaystyle 171

, which is incorrect)
- For

\displaystyle p = 17

\displaystyle 17^2 - 2 = 287

The pattern of

\displaystyle p^2 - 2

using consecutive prime numbers holds perfectly for all terms except

\displaystyle 171

, which should be

\displaystyle 167

. Therefore,

\displaystyle 171

is the odd man out.

Hence, **Option A** 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.

Related Comparison Tables

Cardinal vs Ordinal Utility: Measuring Satisfaction Promissory Note vs Bill of Exchange: Negotiable Instruments

Ready to Master Number Series, Coding and Decoding?

Practice all 217 questions with instant feedback, earn XP, track your streaks, and ace your CA Foundation exam.

Start Practicing — It's Free

Find the odd man out from the following series : 7,23,47,119,171,287\displaystyle 7, 23, 47, 119, 171, 2877,23,47,119,171,287.

Options

Correct Answer

All Options:

Detailed Solution & Explanation

About This Chapter: Number Series, Coding and Decoding

Related Comparison Tables

More Questions from Number Series, Coding and Decoding

Ready to Master Number Series, Coding and Decoding?

Find the odd man out from the following series : $\displaystyle 7, 23, 47, 119, 171, 287$ .