Find odd man out of the series 145, 197, 257, 325, 399

Option b: 399. Solution: Let's analyze the mathematical structure of the terms in the series: 145, 197, 257, 325, 399 . Each correct term follows the pattern n2 + 1 for consecutive even numbers n starting from 12 : - For n = 12 : 122 + 1 = 144 + 1 = 145 - For n = 14 : 142 + 1 = 196 + 1 = 197 - For n = 16 : 162 + 1 = 256 + 1 = 257 - For n = 18 : 182 + 1 = 324 + 1 = 325 - For n = 20 : 202 + 1 = 400 + 1 = 401 (the series lists 399 , which is 202 - 1 ) Since 399 violates the n2 + 1 pattern, it is the odd man out. Hence, Option B is the correct answer.

Find odd man out of the series $145, 197, 257, 325, 399$

The correct answer is Option b: $399$. Let's analyze the mathematical structure of the terms in the series: $145, 197, 257, 325, 399$. Each correct term follows the pattern $n^2 + 1$ for consecutive even numbers $n$ starting from $12$: - For $n = 12$: $12^2 + 1 = 144 + 1 = 145$ - For $n = 14$: $14^2 + 1 = 196 + 1 = 197$ - For $n = 16$: $16^2 + 1 = 256 + 1 = 257$ - For $n = 18$: $18^2 + 1 = 324 + 1 = 325$ - For $n = 20$: $20^2 + 1 = 400 + 1 = 401$ (the series lists $399$, which is $20^2 - 1$) Since $399$ violates the $n^2 + 1$ pattern, it is the odd man out. Hence, **Option B** is the correct answer.

Number Series, Coding and DecodingMCQMTP Nov. 20Question 2183 of 217

All Questions

Find odd man out of the series $\displaystyle 145, 197, 257, 325, 399$

Options

\displaystyle 145

\displaystyle 399

\displaystyle 257

\displaystyle 325

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Correct Answer

✅ Option b — $\displaystyle 399$

All Options:

A $\displaystyle 145$
B $\displaystyle 399$
C $\displaystyle 257$
D $\displaystyle 325$

Detailed Solution & Explanation

Let's analyze the mathematical structure of the terms in the series:

\displaystyle 145, 197, 257, 325, 399

.
Each correct term follows the pattern

\displaystyle n^2 + 1

for consecutive even numbers

\displaystyle n

starting from

\displaystyle 12

:
- For

\displaystyle n = 12

\displaystyle 12^2 + 1 = 144 + 1 = 145

- For

\displaystyle n = 14

\displaystyle 14^2 + 1 = 196 + 1 = 197

- For

\displaystyle n = 16

\displaystyle 16^2 + 1 = 256 + 1 = 257

- For

\displaystyle n = 18

\displaystyle 18^2 + 1 = 324 + 1 = 325

- For

\displaystyle n = 20

\displaystyle 20^2 + 1 = 400 + 1 = 401

(the series lists

\displaystyle 399

, which is

\displaystyle 20^2 - 1

)

Since

\displaystyle 399

violates the

\displaystyle n^2 + 1

pattern, it is the odd man out.

Hence, **Option B** 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.

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Exam Strategy Tip

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

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Find odd man out of the series 145,197,257,325,399\displaystyle 145, 197, 257, 325, 399145,197,257,325,399

Options

Correct Answer

All Options:

Detailed Solution & Explanation

About This Chapter: Number Series, Coding and Decoding

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Find odd man out of the series $\displaystyle 145, 197, 257, 325, 399$