Two pipes, A and B, can fill a tank in 10 minutes and 20 minutes, respectively. Pipe C can empty the tank in 30 minutes. All three pipes are opened to...
Question
Two pipes, A and B, can fill a tank in 10 minutes and 20 minutes, respectively. Pipe C can empty the tank in 30 minutes. All three pipes are opened together at the start, but pipe C is closed 2 minutes before the tank is filled. In what time will the tank be full (in minutes)?