A water tank has three taps A, B and C. Tap A, when opened,can fill the water tank alone in 4 hours. Tap B, when opened, can fill the water tank alone in 6 hours and tap C, when opened, can empty the water tank alone in 3 hours. If taps A, B and C are opened simultaneously, how long will it take to fill the tank completely?
Select the correct option:
A) 10 hours
B) 8 hours
C) 18 hours
D) 12 hours
E) None of these
Required time to fill the tank   = 1 /(1/4+1/6)−1/3=1 /5/12−1/3=1 /1/12=12h   Answer 12 hours
<result>D</result>
A water tank has three taps A, B and C. Tap A, when opened,can fill the water tank alone in 4 hours. Tap B, when opened, can fill the water tank alone in 6 hours and tap C, when opened, can empty the water tank alone in 3 hours. If taps A, B and C are opened simultaneously, how long will it take to fill the tank completely?