Multiple choice

A can complete a job in 9 days, B in 10 days and C in 15 days. B and C start the work and are forced to leave after 2 days. The time taken to complete the remaining work is A एक काम को 9 दिनों में पूरा कर सकता है, B, 10 दिनों में और C, 15 दिनों में पूरा कर सकता है। B और C काम शुरू करते है और 2 दिन बाद छुट्टी पर भेज दिये जाते है। शेष काम को पूरा करने में लगा समय है-

  1. 6 days/दिन

  2. 9 days/दिन

  3. 10 days/दिन

  4. 13 days/दिन
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A's work rate = 1/9 per day. B's work rate = 1/10 per day. C's work rate = 1/15 per day. B and C work together for 2 days: work done = 2(1/10 + 1/15) = 2(3/30 + 2/30) = 2(5/30) = 1/3. Remaining work = 1 - 1/3 = 2/3. A completes 2/3 of work at rate 1/9, so time = (2/3)/(1/9) = (2/3)×9 = 6 days.

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