Two pipes A and B can fill a cistern in minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if the pipe B is turned off after?
A. 5 min
B. 9 min
C. 10 min
D. 15 min
Answer:B
Two pipes A and B can fill a cistern in minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if the pipe B is turned off after?
A. 5 min B. 9 min C. 10 min D. 15 min