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Railways PYQCBT 1 2016

RRB NTPC · Question 71

A completes 2/5 of a work in X days. Then he calls B and they together finish the remaining work in 6 days. If B alone takes 100/6 days, find the value of X. A. 10 days B. 50/3 days C. 20 days D. 40 days

  1. B

  2. C

  3. A

  4. D

Show answer & explanation

Answer: (C) A

Explanation

B does 6/100 of the work per day. Together they finish the remaining 3/5 in 6 days, so A + B = 1/10 a day and A = 1/10 − 6/100 = 1/25. A does 2/5 of the work in (2/5) × 25 = 10 days.