A tank is connected with 8 pipes. Some of them are inlet pipes and rest work as outlet pipes. Each of the inlet pipe can fill the tank in 8 hours, individually, while each of those that empty the tank i.e., outlet pipe, can empty it in 6 hours individually. If all the pipes are kept open when the tank is full, it will take exactly 6 hours for the tank to empty. How many of these are inlet pipes?

Q. A tank has two inlet pipes which can fill the empty tank in 12 hours and 15 hours working alone and one outlet pipe which can empty the full tank in 8 hours working alone. The inlet pipes are kept open for all the time but the outlet pipe was opened after 2 hours for one hour and then again closed for 2 hours then once again opened for one hour. This pattern of outlet pipe continued till the tank got completely filled. In how many hours the tank has been filled, working on the given pattern?

Q. An empty tank is connected with pipes A, B and C. A and B inlet pipes and they fill the tank in $6$ hours and $8$ hours respectively. While C is an outlet pipe and it empties the completely filled tank in $5$ hours. Find the time in which the tank will be completely filled if all the pipes are opened together.

Q. How long will it take to empty the tank if both the inlet pipe A and the outlet pipe B are opened simultaneously?
I. A can fill the tank in $6$ minutes.
II. B can empty the full tank in $8$ minutes.

Q. Pipe A takes $\frac{3}{4}$ of the times required by pipe B to fill the empty tank individually. When an outlet pipe C is also opened simultaneously with pipe A and pipe B, it takes$\frac{3}{4}$ more time to fill the empty tank than it takes, when only pipe A and pipe B are opened together, If it takes to fill 33 hours when all the three pipes are opened simultaneously, then in what time pipe C can empty the full tank operating alone?