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Railways PYQCBT 1 2016

RRB NTPC · Question 75

Find the missing (?) in the series: 9, 4, 16, 6, 36, 9, 81, ? A. 12 B. 10 C. 11 D. 13

  1. C

  2. D

  3. A

  4. B

Show answer & explanation

Answer: (B) D

Explanation

The series alternates two patterns. Odd terms 9, 16, 36, 81 are squares of 3, 4, 6, 9. Even terms 4, 6, 9, ? increase by 2, 3, then 4, so the next is 9 + 4 = 13.