Two pipes A and B can separately fill a tank in 12 and 15 minutes respectively. A third pipe C can drain off 45 liters of water per minute. If all the pipes are opened, the tank can be filled in 15 minutes. What is the capacity of the tank?
Choose the correct choice from the following:  A) 590 liters  B) 540 liters  C) 740 liters  D) 560 liters  E) 580 liters
1/12 + 1/15 - 1/x   = 1/15   x = 12   12 * 45= 
<gadget id="calculator">12 * 45</gadget>
<output>540</output>
540   Answer:540 liters
<result>B</result>
Two pipes A and B can separately fill a tank in 12 and 15 minutes respectively. A third pipe C can drain off 45 liters of water per minute. If all the pipes are opened, the tank can be filled in 15 minutes. What is the capacity of the tank?