Multiple choice

A tank gets filled by a pipe in 2 hours. But due to a leak, it takes 30 more minutes to fill the tank. How long will it take a full tank to get emptied by the leak, when the pipe is closed?

  1. 10 hours

  2. 2 hours 45 minutes

  3. 5 hours

  4. 2 hours 30 minutes

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pipe rate = 1/2 tank/hour. With leak: effective rate = 1/2.5 = 2/5 tank/hour. Leak rate = 1/2 - 2/5 = 1/10 tank/hour (leak empties). So full tank empties in 10 hours by leak alone. Answer A is correct.