Pipe A can fill a tank in 6 hours. Due to a leak at the bottom, it takes 12 hours for the pipe A to fill the tank. In what time can the leak alone empty the full tank? Answers:
A) 67	B) 88	C) 18	D) 26	E) 12
Let the leak can empty the full tank in x hours 1/6 - 1/x = 1/12   =&gt; 1/x = 1/6 - 1/12 = (3 - 2)/12 = 1/12   =&gt; x = 12. Answer:12
<result>E</result>
Pipe A can fill a tank in 6 hours. Due to a leak at the bottom, it takes 12 hours for the pipe A to fill the tank. In what time can the leak alone empty the full tank?