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Railways PYQCBT 1 2020

RRB NTPC · Question 20

The smallest number which should be subtracted from the smallest number of four digits to make it a perfect square is:

  1. 120

  2. 159

  3. 39

  4. 24

Show answer & explanation

Answer: (C) 39

Explanation

The smallest four-digit number is 1000. The largest square below it is 31² = 961, so 1000 − 961 = 39 must be subtracted.