There are two inlet pipes and an outlet pipe attached to a tank. The first inlet pipe can fill the tank in 25 minutes and the second inlet pipe takes 5 minutes more than the first inlet pipe. It can be emptied completely in 6 minutes by the outlet pipe. If the two inlets are opened at 06:00 pm and 06:04 pm respectively and the outlet at 06:12 pm then the tank will be emptied at (approximately)