# Pipes & Cistern

Two pipes can fill a tank in 6hours and 8 hours .While a third pipe empties the full tank in 12hours.If all the three pipes are operate simultaneously, In how much time  will the tank be filled ?
A)4 hours
B)4hours 48min
C)5hours
D)5hours 48min

A tap can fill a tank in 6hrs.After half the tank is filled, three more similar taps are opened. What is the total time taken to fill the tank completely ?

A)3hrs
B)3hrs 15 min
C)3hrs 45 min
D)4hrs

Two pipes can fill a tank in 8 hours and 10 hours .If two pipes are operate simultaneously, In how much time  will the tank be filled ?

A)4hrs 18min
B)10min
C)4hrs
D)12hrs 10min

Two pipes  A and B  can fill a tank in 20 minutes and 40 minutes.If both pipes are opened simultaneously , after how much time should B be closed  so that the tank is full in 18 minutes ?

A)10 min
B)4 min
C)8 min
D)7min