Three pipes A, B and C can fill a tank in 15 minutes, 20 minutes and 30 minutes respectively. The pipe C is closed 6 minutes before the tank is filled. In what time will the tank be full?(CTS COMPANY)

Three pipes A, B and C can fill a tank in 15 minutes, 20 minutes and 3

1.	Three pipes A, B and C can fill a tank in 15 minutes, 20 minutes and 30 minutes respectively. The pipe C is closed 6 minutes before the tank is filled. In what time will the tank be full?(CTS COMPANY)
A.	8 min
B.	5 min
C.	12 min
D.	6 min
Answer» B. 5 min