Two pipes X and Y can fill a cistern in 21 hours and 24 hours, respectively. The pipes are opened simultaneously, and it is found that due to a leakage in the bottom it takes 48 minutes more to fill the cistern. When the cistern is full, in how much time will the leak empty it if no pipe is open during that time?

Three taps A, B, and C can fill an empty tank in 30 minutes, 20 minutes, and 10 minutes respectively. When the tank is empty, all three taps are opened. Taps A, B, and C release chemical solutions P, Q, and R respectively. What is the proportion of solution R in the tank after 3 minutes?

Two inlet pipes J and T can fill a tank in 120 minutes and 144 minutes respectively. If an outlet pipe Z is opened along with them, all three pipes together fill the tank in 240 minutes. How long will pipe Z alone take to empty the full tank?