A bath can be filled by the cold water pipe in 10 minutes and by the hot water pipe in 15 minutes. A person leaves the bathroom after turning on both the pipes' Ile returns just when the bath should have been full. Finding however, the waste pipe was open, he closes it. In 4 minutes more, the bath is full. In what time will the waste water pipe empty it? `6\ m inu t e s` b. `\ 8\ m inu t e s` c. `9\ m inu t e s` d. none of these

Options

A. 9 min
B. 12 min
C. 15 min
D. 14 min

Answer

C