Three pipes A, B and C can fill a tank in 6 hours, 9 hours and 12 hours respectively. B and C are opened for half an hour, then A is also opened. The time taken by the three pipes together to fill the remaining part of the tank is :
Three pipes A, B and C can fill a tank in 6 hours, 9 hours and 12 hours respectively. B and C are opened for half an hour, then A is also opened. The time taken by the three pipes together to fill the remaining part of the tank is :
[A]2 hours
[B]2.5 hours
[C]3 hours
[D]3.5 hours
2.5 hours
Part of the tank filled by pipe B and C in half an hour
Remaining part
Part of the tank filled by three pipes in an hour
∴ Time to fill remaining part
Hence option [B] is correct answer.
