aiming4mba wrote:

Pipe A will fill a tank in 24 minutes and pipe B will fill the same tank in 36 minutes. There is a drain pipe which will empty the tank in 30 minutes. If the drain pipe is opened 8 minutes after A and B are opened, when will the tank be full?

Hi Assume the Volume of tank is 360 ( i chose this because its the LCM of 24,30 and 36).

So flow of pipe A = 15 L/min

Flow of Pipe B = 10 l/min

Flow of drain pipe and pipe a and B are open = 25-12=13 L/Min

Flow when pipe A and B are open = 15+10 =25 L

Drain = 12 L/min

so 8 mins only and B are open volume filled = 25*8= 200 L.

So time required to fill the remaining volume (360-200) = 160 / 13

= 12.3 Mins

So Tank will fill up in 12 Mins and 18 seconds.

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