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Railways PYQCBT 1 2016

RRB NTPC · Question 91

The average of the first 20 multiples of 12 is: A. 124 B. 120 C. 126 D. 130

  1. A

  2. B

  3. C

  4. D

Show answer & explanation

Answer: (C) C

Explanation

The first 20 multiples of 12 are 12 × 1, 12 × 2, …, 12 × 20. Their average = 12 × (average of 1 to 20) = 12 × 21/2 = 12 × 10.5 = 126.