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Railways PYQCBT 1 2016

RRB NTPC · Question 39

Twice the difference between two numbers is equal to their sum. If one number is 15, find the other number.

  1. 15 or 45

  2. 10 or 30

  3. 5 or 45

  4. 20 or 35

Show answer & explanation

Answer: (C) 5 or 45

Explanation

Let the other number be x. If x > 15: 2(x − 15) = x + 15, so x = 45. If x < 15: 2(15 − x) = x + 15, so 3x = 15 and x = 5. The other number is 5 or 45.