Pipes A and B can fill a tank in 10 hours and x hours respectively. Pipe C alone can empty the full tank in 15 hours. When all three pipes are opened simultaneously for 8 hours, 60% of the tank is filled. In how many hours can pipes B and C together empty two-fifth of the tank?

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?