# A tank can be filled by a tap 20 min & by another 25 min. Both taps are kept open for 5 min & then second is turned off.

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A tank can be filled by one tap 20 minute and by another 25 minute. Both the taps are kept open for 5 minute and then second is turned off. In how many minute more is the tank completely filled.

posted Aug 12, 2015

Let the tank be 1000 liters. Discharge rate of first tap is 1000/20 or 50 liter per minute. Smilarly discharge of the second tap is 40 liter per minute. When both the taps are open for five minutes, a discharge of (50+40)*5 or 450 liter has taken place and we are left with 550 liters to be filled. This can be done in 550/50 or 11 minutes by the first tap alone. This problem can also be solved by assuming tank of Q liter capacity. In the answer Q will cancel in the numerator and denominator.

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A tank can be filled by the Tap A in 4 Hrs and by Tap B in 6 Hrs. The same tank can be emptied by the Tap C in 8 Hrs. Now suppose we keep all three taps on then how much time it will take to fill?

Three taps together drains a tank in 5 hours.
If first tap drains this tank in 10 hours alone.
Then what will be the minimum hours taken by the second tap to drain this tank ?