Multiple choice

A number series is given below in which only one number is wrong. Find out the wrong number. 9 9 12 18 26 39

  1. 9

  2. 12

  3. 18

  4. 26

  5. 39
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The differences between consecutive terms are: 9-9=0, 12-9=3, 18-12=6, 26-18=8, 39-26=13. The pattern of differences should be 0, 3, 6, 9, 12. Replacing 26 with 27 makes the differences 0, 3, 6, 9, 12, which fits the pattern.

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