Pipe and cisterns competition math

An outlet pipe can empty a cistern in 5h . In what time will the pipe empty 2/5 part of cistern ?

Two inlet pipes A and B can fill an empty cistern in 35 hours and 52.5 hours respectively while Pipe C is an outlet pipe that can drain the filled cistern in 17. 5 hours. When the cistern is full Pipe C is left open for an hour, then closed and Pipe A is opened for an hour, closed and Pipe B is opened for an hour. The process continues till the cistern is empty. How many hours will it take for the filled cistern to be emptied ? (a)301 (b)313 (c)298 (d)315

Two inlet pipes A & B can fill an empty cistern in 12 hours & 36 hours respectively while Pipe C is an outlet pipe that can drain the filled cistern in 6 hours. When the cistern is full Pipe C is left open for an hour, then closed & Pipe A is opened for an hour, closed and Pipe B is opened for an hour. The process continues till the cistern is empty. How many hours will it take for the filled cistern to be emptied?

Pipes A and C can fill an empty cistern in 32 and 48 hours, respectively while Pipe B can drain the filled cistern in 24 hours. If the three pipes are turned on together when the cistern is empty, how many hours will it take for the cistern to be 2/3 full?

Pipe A and B can fill a cistern in 10 hours and 15 hours respectively. When a third pipe C which works as an outlet pipe is also open then the cistern can be filled in 18 hours. The outlet pipe can empty a full cistern in :

Pipe A and B can fill a cistern in 10 hours and 15 hours Respectively. When a third pipe C which works as an outlet pipe is also open then the cistern can be filled in 18 hours. The outlet pipe can empty a full cistern in :

Two pipes can fill a cistern in 3 hours and 4 hours respectively and a waste pipe can empty it in 2 hours. If all the three pipes are kept open, then the cistern will be filled in :

An outlet pipe can empty a cistern in 30 min, then what part of the cistern will it empty in 1 min?