Multiple choice

Two pipes A and B can separately fill a tank in 2 hours and 3 hours, respectively. If both the pipes are opened simultaneously in the empty tank, then the tank will be filled in

  1. 1 hour 12 minutes

  2. 2 hours 30 minutes

  3. 1 hour 15 minutes

  4. 1 hour 20 minutes
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A Correct answer
Explanation

Combined rate = 1/2 + 1/3 = 5/6 tanks per hour. Time = 1 / (5/6) = 6/5 hours = 1.2 hours = 1 hour 12 minutes.

AI explanation

Using the formula for combined work, the part of the tank filled in one hour by both pipes is the sum of their individual rates, giving 1/2 + 1/3. Finding a common denominator yields 3/6 + 2/6 = 5/6. The total time to fill the tank is the reciprocal of this combined rate, so the tank fills in 6/5 hours, which equals 1 hour and 12 minutes.

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