Pipes A can fills 50% more then Pipes B in the same time. Pipes B can fill the tank in 30 hr. only B starts filling the tank and after 12 hr A also open. How many hours should Pipes A and B both open to filled the remaining tank.
1
1.8 hr
2
3.6 hr
3
5.4 hr
4
7.2 hr
5
9 hr