Multiple choice

Find the wrong number in the following number series- 15 19 36 71 135 235

  1. 36

  2. 71

  3. 15

  4. 9

  5. 235
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A Correct answer
Explanation

The pattern is: add 4, then multiply by 2, then subtract 3, then multiply by 2, then subtract 7. Starting from 15: 15+4=19, 19×2=38, 38-3=35, 35×2=70, 70-7=63... wait, that doesn't match. Let me reconsider: the pattern could be 15+4=19, 19×2-2=36, 36×2-1=71, 71×2-7=135, 135×2-35=235. If 36 is replaced by 38, the pattern would be 19×2-2=36 (should be 38×2-?), suggesting 36 breaks the pattern and is the wrong number.

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