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

Option a: 342. Solution: We are given the series: 7, 26, 63, 124, 215, ?, 511 Let's express each term in relation to perfect cubes: - 7 = 23 - 1 - 26 = 33 - 1 - 63 = 43 - 1 - 124 = 53 - 1 - 215 = 63 - 1 The terms follow the pattern n3 - 1 for consecutive integers n starting from 2 . Therefore, the missing term is 73 - 1 : 73 - 1 = 343 - 1 = 342 Let's verify the next term in the series: 83 - 1 = 512 - 1 = 511 This matches the final term perfectly. Hence, Option A is the correct answer.

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

The correct answer is Option a: 342. We are given the series: $7, 26, 63, 124, 215, ?, 511$ Let's express each term in relation to perfect cubes: - $7 = 2^3 - 1$ - $26 = 3^3 - 1$ - $63 = 4^3 - 1$ - $124 = 5^3 - 1$ - $215 = 6^3 - 1$ The terms follow the pattern $n^3 - 1$ for consecutive integers $n$ starting from $2$. 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.

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

All Questions

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

Options

A342

B343

C441

D421

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

Correct Answer

✅ Option a — 342

All Options:

A342
B343
C441
D421

Detailed Solution & Explanation

We are given the series:

\displaystyle 7, 26, 63, 124, 215, ?, 511

Let's express each term in relation to perfect cubes:
-

\displaystyle 7 = 2^3 - 1

\displaystyle 26 = 3^3 - 1

\displaystyle 63 = 4^3 - 1

\displaystyle 124 = 5^3 - 1

\displaystyle 215 = 6^3 - 1

The terms follow the pattern

\displaystyle n^3 - 1

for consecutive integers

\displaystyle n

starting from

\displaystyle 2

.
Therefore, the missing term is

\displaystyle 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.

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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The number in place of question mark in: 7,26,63,124,215,?,511\displaystyle 7, 26, 63, 124, 215, ?, 5117,26,63,124,215,?,511 is