Pipe A can fill 50% of the tank in 6 hours and Pipe B can fill the same tank in 18 hours. If both the pipes are opened at the same time, in how much time (in minutes) will the empty tank be filled?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 432 minutes.
Pipe A can fill 50% of the tank in 6 hours
Pipe A can fill 100% of the tank in 12 hours
Pipe B can fill 100% of the tank in 18 hours
Total work (LCM of 12 and 18) = 36 units
Efficiency of Pipe A = 36/12 = 3 unit/hr
Efficiency of Pipe B = 36/18 = 2 unit/hr
Total Efficiency of pipe A and B = 3 + 2 = 5 unit/hr
Hence, the required time taken = 36/5 hr
⇒ (36 × 60)/5 = 432 minutes