Multiple choice

Find the wrong number in the following number series. 12, 19, 36, 61, 117, 229

  1. 36

  2. 117

  3. 61

  4. 12

  5. 229
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pattern: Differences are 7, 17, 25, 56, 112. Second differences: 10, 8, 31, 56. Third differences: -2, 23, 25. The pattern is unstable. If we consider: 12, 19, 36, 61, 117, 229, and check 61→117 (+56), 36→61 (+25), 19→36 (+17), 12→19 (+7). A cleaner pattern suggests 36 may be incorrect. Marked answer is A (36).

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