Multiple choice

Pipe A can fill a tank in 3 hours. But due to a leakage, it takes 3.5 hours for the tank to be filled. How much time will the leakage take in emptying the tank, if the tank is initially full?

  1. 21 hours

  2. 20 hours

  3. 18 hours

  4. 10.5 hours
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rate of pipe = 1/3. Rate of pipe + leak = 1/3.5 = 2/7. Leak rate = 1/3 - 2/7 = (7-6)/21 = 1/21. Leak empties in 21 hours.

AI explanation

Using the rate formula, pipe A fills 1/3 of the tank per hour. Due to the leakage, the net filling rate drops to 1/3.5, which equals 2/7 of the tank per hour. The leak empties at a rate of 1/3 minus 2/7, which is 7/21 minus 6/21, resulting in 1/21 of the tank per hour. Therefore, the leak alone takes 21 hours to empty a full tank. The answer is 21 hours.

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