Three taps A, B and C can fill an tank in 50, 60 and 75 hours respectively. How long (in hours) would the three taps take to fill the tank if all of them are opened together?

Three taps A, B and C can fill an tank in 50, 60 and 75 hours respecti

1.	Three taps A, B and C can fill an tank in 50, 60 and 75 hours respectively. How long (in hours) would the three taps take to fill the tank if all of them are opened together?
A.	12
B.	15
C.	20
D.	10
Answer» D. 10