A pipe can fill a tank in 7 hours. Another pipe can empty the filled tank in 9 hours. If both the pipes are opened simultaneously, then the time (in hours) in which the tank will be two-third filled, is:
Given:
Pipe A fills the tank in 7 hours
Pipe B empties the tank in 9 hours
Required work = of the tank.
Solution:
work rate = per hour.
work rate = - per hour.
Net rate when both are open =
Net rate = per hour
Time = = 21 hours
Alternate Method:
Time taken to fill the tank =
Required work = of the tank = 21 hours
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100 Questions
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90 Mins English English100 Questions100 Marks90 Mins English English40 Questions30 Marks25 Mins EnglishTwo pipes, P and Q, together can fill a tank in 5 hours. If pipe P alone can fill the tank in 10 hours, then how much time (in hours) will pipe Q alone take to fill the tank?
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