Question
Two pipes A and B can fill a tank in 15 hours and 20 hours respectively while a third pipe C can empty the full tank in 25 hours . All the three pipes are opened in the beginning . After 10 hours. C is closed. In how much time , will the tank be full ?
Answer: Option A
Was this answer helpful ?
Part filled in 10 hours = `10(1/15 + 1/20 - 1/25) = 23/30`
Remaining part = `(1 - 23/30) = 7/30`
(A + B)'s 1 hour's work = `(1/15 + 1/20) = 7/60`.
`7/60 : 7/30 : : 1 : x or x = (7/30 xx 1 xx 60/7)` = 2 hours
`:.` The tank will be full in (10 + 2) hrs. = 12 hrs.
Was this answer helpful ?
More Questions on This Topic :
Latest Videos
Latest Test Papers
Submit Solution