Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank______? May 12, 2026August 7, 2019 A.10 min. 20 sec. B.11 min. 45 sec. C.12 min. 30 sec. D.14 min. 40 sec. Answer=Option D