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Railways PYQCBT 1 2016

RRB NTPC · Question 50

If ‘-’ and ‘×’ signs as well as ‘7’ and ‘3’ are interchanged, then which of the one following is correct? A. 20 × 1 – 7 = 3 B. 1 × 20 – 7 = 20 C. 3 – 7 × 1 = 20 D. 20 – 3 × 1 = 7

  1. A

  2. B

  3. D

  4. C

Show answer & explanation

Answer: (D) C

Explanation

Swapping − ↔ × and 7 ↔ 3 turns option C, 3 − 7 × 1 = 20, into 7 × 3 − 1 = 20, which is true (21 − 1 = 20). The other options are false after the same swaps.