A pipe can filled a tank in 40 minutes and another pipe can empty it in 1hour. If the tank is already half full and both the taps are opened together, then the tank is filled in how many minutes?
Choose one
A) 25min  B) 20min  C) 15min  D) 10min  E) 30min
T = 1/2 (25*50 / 50-25) = 25 minutes   Tank is filled in 25 minutes   25minnswer is 25min
<result>A</result>
A pipe can filled a tank in 40 minutes and another pipe can empty it in 1hour. If the tank is already half full and both the taps are opened together, then the tank is filled in how many minutes?