Three taps, A, B and C, can fill a tank in $20$, $30$ and $40$ minutes, respectively. All the taps are opened simultaneously, and after $5$ minutes, tap A is closed and then after another $6$minutes, tap B is closed. At the moment, a leak developed, which can empty the full tank in $60$ minutes. What is the total time required for the tank to get completely full?

Of the three pipes, the first two can fill an empty tank in 10.8 and 21.6 hours respectively, while the third pipe can empty the tank in 18 hours. If the tank is empty and all the three pipes are opened together then in how many hours will tank fill?

Pipe A in comparison to pipe B fills a tank in one fourth time. Pipe C in comparison to pipe A takes 3 times more time to fill the tank. If the three pipes are opened together, the tank is filled in 24 hours. If Pipe C is not opened, how much time will it take to fill the tank?

Two inlet pipes A and B can fill an empty tank in 22 and 33 hours respectively. They are opened together but pipe A is turned off 3 hours before the tank is filled. How many hours are required to fill the tank completely by both pipes?

Two pipes separately take $5$ hours and $8$ hours respectively to fill a tank. The third pipe takes $3.2$ hours to drain out the water from the tank. How much time will all the three pipes take to fill the completely empty tank?