Question : Pipes A, B and C can fill an empty tank in $\frac{30}{7}$ hours if all three pipes are opened simultaneously. A and B are filling pipes and C is an emptying pipe. Pipe A can fill the tank in 15 hours and pipe C can empty it in 12 hours. In how much time (in hours) can

Question : Pipe P alone can fill a tank in 18 hours and Pipe Q alone can fill the same tank in 24 hours. If both the pipes are opened on alternate hours one at a time and pipe Q is opened for the first hour, then in how much time the tank will be full?

Question : Pipes A and B together can fill a tank in 10 hours. Pipes B and C together can fill the same tank in 12 hours. Pipes A and C together can fill the same tank in 15 hours. In how many hours can pipe B alone fill the same tank?

Question : Pipe A can fill 50% of the tank in 6 hours and Pipe B can fill the same tank in 18 hours. If both the pipes are opened simultaneously, how much time (in minutes) will the empty tank be filled?

Question : Pipe X can fill a tank in 20 hours and pipe Y can fill the tank in 35 hours. Both the pipes are opened at alternate hours. If pipe Y was opened first, then how much time (in hours) does it take to fill the tank?