Pipes A and B are emptying pipes and can empty a tank in 6 hours and 16 hours respectively. C is a filling pipe. All the 3 pipes were opened together. They took 80 minutes to empty 5/18th of the tank. Pipe C alone can fill the tank in?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 48
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If pipe A, B, and C are opened together, they took 80 minutes to empty the tank. We know that 80 minutes = 4/3 hrs. So, the tank emptied by pipe A and B in 4/3 hrs = -4/3[(1/6) + (1/16)] = -11/36 of the tank Here, the negative sign only shows that the tank is emptied by Pipe A and B. Tank emptied by pipe A, B, and C in 4/3 hrs = -5/18 = - 10/36 of the tank. Tank filled by pipe C in 80 minutes = -10/36 - (-11/36) = 1/36 of the tank Tank filled by pipe C in 60 minutes = (1 × 60)/(36 × 80) = 1/48 of the tank Hence, Pipe C alone can fill the tank in 48 hours. |