Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opended together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank?
Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opended together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank? Correct Answer 14 min 40 sec
By pipe A and B Part filled in 4 minutes = 4×( 1/15 + 1/20) = 7/15 Remaining part = 1 - 7/15 = 8/15 part filled by B in 1 minute = 1/20 By B, 1/20 part can be filled in 1 minute 8/15 part can be filled in ( 20×8)o/15 = 10 min 40 sec So, total time required ( 4 min + 10min 40 sec) = 14 min 40 sec.