Tap X can fill a tank in 12 minutes and tap Y can fill the same tank is 15 minutes another tap Z can...........

Quantitative Aptitude (Insurance) Time and work

Tap X can fill a tank in 12 minutes and tap Y can fill the same tank is 15 minutes, another tap Z can empty the tank in 10 minutes. If tap X and tap Y are opened & after 6 minutes tap Z is also opened. Then find the total time taken to fill the tank ?

8 minutes