Number Series, Coding, Odd Man OutMTP Dec 22 Series IIQuestion 2065 of 217
All Questions

Find the missing term of the following series: 7,26,63,124,215,342?\displaystyle 7, 26, 63, 124, 215, 342?

Options

A391\displaystyle 391
B421\displaystyle 421
C481\displaystyle 481
D511\displaystyle 511
For any discrepancies in this question, email contact@cadada.in

Correct Answer

✅ Option d — 511\displaystyle 511

All Options:

  • A391\displaystyle 391
  • B421\displaystyle 421
  • C481\displaystyle 481
  • D511\displaystyle 511

Detailed Solution & Explanation

To find the missing term of the series 7,26,63,124,215,342,?\displaystyle 7, 26, 63, 124, 215, 342, ?, let us analyze the relation of each term to perfect cubes:

- 1st term: 23−1=8−1=7\displaystyle 2^3 - 1 = 8 - 1 = 7
- 2nd term: 33−1=27−1=26\displaystyle 3^3 - 1 = 27 - 1 = 26
- 3rd term: 43−1=64−1=63\displaystyle 4^3 - 1 = 64 - 1 = 63
- 4th term: 53−1=125−1=124\displaystyle 5^3 - 1 = 125 - 1 = 124
- 5th term: 63−1=216−1=215\displaystyle 6^3 - 1 = 216 - 1 = 215
- 6th term: 73−1=343−1=342\displaystyle 7^3 - 1 = 343 - 1 = 342

Following this logical pattern, the next term must be:
- 7th term: 83−1=512−1=511\displaystyle 8^3 - 1 = 512 - 1 = 511

Therefore, the mathematical answer is **511\displaystyle 511**, which corresponds to **Option D**.

*Note on Answer Key Discrepancy:* The textbook/exam answer key lists **Option B** (421\displaystyle 421) as the correct answer. However, 421\displaystyle 421 does not correspond to any logical progression of the series, while 511\displaystyle 511 perfectly completes the cubic pattern n3−1\displaystyle n^3 - 1. This is a confirmed typographical error in the official answer key, and the mathematically correct option is **Option D**.

Hence, **Option D** is the correct answer.

More Questions from Number Series, Coding, Odd Man Out

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

Find missing term 7,26,63,124,215,342,?\displaystyle 7, 26, 63, 124, 215, 342, ?

Which number should come next 7,26,63,124,215,342,?\displaystyle 7, 26, 63, 124, 215, 342, ?

If CLOCK is coded as 34235 and TIME as 8679, then MOTEL is coded as:

If MOUSE, is coded as 34651 and KEY is coded as 217, then how will YES be coded?

In a certain code language PREMONITION is written as 68530492904\displaystyle 68530492904, how will the word MONITOR be written in that code language?

Ready to Master Number Series, Coding, Odd Man Out?

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

Start Practicing — It's Free