Pipe A can completely fill an empty tank in 11 hours. Pipe B can empty the same completely filled tank in 15 hours. If they are opened together, in how much time the empty tank will get filled?

41 hours 15 minutes 49 hours 45 minutes 47 hours 30 minutes 39 hours 15 minutes

41 hours 15 minutes

A+ = 11 hrs, B- = 15 hrs, ⇒ Time required by A + B to completely fill the tank = \(\frac{165}{4}\) = \( {41 }_{ 4}^{1 } \) x 60 = 41 hours 15 minutes.