Question 85

Logical Reasoning Alphanumeric series Easy

Find out the wrong number in the following series.

15, 16, 34, 105, 424, 2124, 12756

(A) 16
(B) 34
(C) 424
(D) 2125
✓ Correct Answer: Option D Verified Solution

📘 Step-by-Step Solution & Detailed Explanation:

Pattern Analysis



The rule for this series is: (previous term × n) + n, where 'n' starts at 1 and increases by 1 for each step.



  • (15 × 1) + 1 = 16

  • (16 × 2) + 2 = 34

  • (34 × 3) + 3 = 105

  • (105 × 4) + 4 = 424

  • (424 × 5) + 5 = 2125. The series has 2124 at this position, which breaks the pattern.

  • If we continue from the correct number: (2125 × 6) + 6 = 12756.





The entry given in the series is 2124, but according to the established pattern, it should be 2125.



The wrong number in the series is 2124.

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