- A9
- B6
- C3
- D12
Step-by-Step Solution
A runs the full 18 min filling 18/20 = 9/10. B must supply 1/10, and B fills 1/30 per min, so it ran (1/10) / (1/30) = 3 minutes.
Answer: C) 3
Two pipes A and B can fill a tank in 20 minutes and 30 minutes respectively. Both are opened together, but B is closed after some time so that the tank is full in 18 minutes. After how many minutes was B closed?
Competition practiceTime & Work / Pipes
Master this topic in 30 minutes a day.
Don't just memorise the answer — build a daily practice habit.
Practice 5 Similar Questions Free →All Time & Work / Pipes practice questions
More Time & Work / Pipes practice
Tarun alone can build a garden shed in 16 days, while Uday alone needs 48 days. They…Ravi works three times as fast as Sohan. Together they finish a job in 9 days. How many…A hotel's water tank is filled by an inlet in 7 hours and emptied by an outlet in 21…Pipe P fills a tank in 16 minutes and pipe Q in 24 minutes. Both are opened together,…A is twice as efficient as B. Working together they finish a job in 12 days. How many…