Two pipes X and Y can fill a tank in 60 minutes and 75 minutes respectively. There is also an outlet Z. If all the three pipes are used together, the tank is full in 50 minutes. How much time will be taken by Z to empty the full tank?

Two pipes X and Y can fill a tank in 60 minutes and 75 minutes respect

1.	Two pipes X and Y can fill a tank in 60 minutes and 75 minutes respectively. There is also an outlet Z. If all the three pipes are used together, the tank is full in 50 minutes. How much time will be taken by Z to empty the full tank?
A.	90 minutes
B.	100 minutes
C.	50 minutes
D.	75 minutes
Answer» C. 50 minutes