Multiple choice

Which number is wrong in the series. 6 , 13 , 18 , 25 , 30 , 37 , 40

  1. 25

  2. 30

  3. 37

  4. 40
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The series alternates between adding 7 and adding 5: 6 + 7 = 13, 13 + 5 = 18, 18 + 7 = 25, 25 + 5 = 30, 30 + 7 = 37, 37 + 5 = 42. The number 40 breaks this pattern, as it should be 42 according to the alternating addition rule. This makes 40 the wrong number in the sequence.

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