Find out the next number in the following series $7, 11, 13, 17, 19, 23, 25, 29$?

The correct answer is Option b: 31. We are given the series: $7, 11, 13, 17, 19, 23, 25, 29, \dots$ Let's find the difference between consecutive terms in the series: - $11 - 7 = 4$ - $13 - 11 = 2$ - $17 - 13 = 4$ - $19 - 17 = 2$ - $23 - 19 = 4$ - $25 - 23 = 2$ - $29 - 25 = 4$ We observe that the differences alternate between $+4$ and $+2$. Following this alternating pattern, the next difference must be $+2$. Therefore, the next term is calculated as: $$29 + 2 = 31$$ Hence, **Option B** is the correct answer.

Number Series, Coding and DecodingMCQPYQ Nov 18Question 2010 of 217

All Questions

Find out the next number in the following series $\displaystyle 7, 11, 13, 17, 19, 23, 25, 29$ ?

Options

A30

B31

C32

D33

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Correct Answer

✅ Option b — 31

All Options:

Detailed Solution & Explanation

We are given the series:

\displaystyle 7, 11, 13, 17, 19, 23, 25, 29, \dots

Let's find the difference between consecutive terms in the series:
-

\displaystyle 11 - 7 = 4

\displaystyle 13 - 11 = 2

\displaystyle 17 - 13 = 4

\displaystyle 19 - 17 = 2

\displaystyle 23 - 19 = 4

\displaystyle 25 - 23 = 2

\displaystyle 29 - 25 = 4

We observe that the differences alternate between

\displaystyle +4

and

\displaystyle +2

.
Following this alternating pattern, the next difference must be

\displaystyle +2

.
Therefore, the next term is calculated as:

29 + 2 = 31

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.

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 out the next number in the following series 7,11,13,17,19,23,25,29\displaystyle 7, 11, 13, 17, 19, 23, 25, 297,11,13,17,19,23,25,29?