Subject: mathqa
Question: two pipes a and b can separately fill a tank in 8 and 10 minutes respectively . a third pipe c can drain off 15 liters of water per minute . if all the pipes are opened , the tank can be filled in 10 minutes . what is the capacity of the tank ?
Option: 
A: 590 liters
B: 160 liters
C: 740 liters
D: 120 liters
Answer: D