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Railways PYQCBT 1 2016

RRB NTPC · Question 36

A & B can finish a work in 12 days, B & C in 15 days and A & C in 20 days. In how many days would A alone finish the work? A. 20 B. 30 C. 40 D. 60

  1. D

  2. B

  3. C

  4. A

Show answer & explanation

Answer: (B) B

Explanation

A + B = 1/12, B + C = 1/15 and A + C = 1/20 of the work per day. Adding and halving, A + B + C = 1/10, so A alone = 1/10 − 1/15 = 1/30: 30 days.