Number Series, Coding and DecodingMCQPYQ Jun 23Question 2031 of 217

The number in place of question mark in: $7, 26, 63, 124, 215, ?, 511$ is

Select Your Answer (Keyboard: A, B, C, D)

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Correct Answer

✅ Option a — 342

We are given the series: $7, 26, 63, 124, 215, ?, 511

\displaystyle <br>Let's express each term in relation to perfect cubes:<br>-

7 = 2^3 - 1

\displaystyle <br>- &#36;26 = 3^3 - 1

- $63 = 4^3 - 1

\displaystyle <br>- &#36;124 = 5^3 - 1

- $215 = 6^3 - 1

\displaystyle <br>The terms follow the pattern

n^3 - 1$ for consecutive integers $n

\displaystyle starting from

\displaystyle .<br>Therefore, the missing term is

7^3 - 1$:

7^3 - 1 = 343 - 1 = 342

Let's verify the next term in the series:

8^3 - 1 = 512 - 1 = 511

This matches the final term perfectly.
Hence, **Option A** is the correct answer.

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.

Exam Strategy Tip

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

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