Two pipes A and B can fill a tank in 15 minutes and 20 minutes respec…

Question

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?

Accepted Answer

Option D. 14 min. 40 sec.. Answer & Solution Answer: Option D Solution: & Part\, filled\, in\, 4\, minutes & = 4 ( 115 + 120 ) = 715 & Remaining\, part = 1 - 715 = 815 & Part\, filled\, by\,B\, in\, 1\, minute = 120 & 120: 815::1:x & x = 815 × 1 × 20 & \,\,\,\,\,\, = 102/3\, & \,\,\,\,\,\, = 10 .\,40\, .…