Question : Two pipes A and B can fill a tank in 12 hours and 18 hours, respectively. Both pipes are opened simultaneously. In how much time will the empty tank be filled completely?

Option 1: 9 hours 30 minutes

Option 2: 8 hours

Option 3: 7 hours 12 minutes

Option 4: 10 hours 24 minutes

Question : A₁, A₂, and A₃ alone can complete a piece of work in 12 hours, 24 hours, and 16 hours respectively. Working together, in how much time will they complete the same work?

Option 1: 5 hours 30 minutes

Option 2: 5 hours 20 minutes

Option 3: 4 hours 20 minutes

Option 4: 3 hours 30 minutes