Multiple choice

Identify the wrong term in the given series. $9, 15, 24, 34, 51, 69, 90$.

  1. $15$
  2. $24$
  3. $34$
  4. $51$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The differences between consecutive terms are: 15-9=6, 24-15=9, 34-24=10, 51-34=17, 69-51=18, 90-69=21. The pattern of differences should be 6, 9, 12, 15, 18, 21. Replacing 34 with 36 makes the differences 6, 9, 12, 15, 18, 21, which is a consistent pattern.

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