Question : Pipes A and B can empty a full tank in 18 hours and 24 hours, respectively. Pipe C alone can fill the tank in 36 hours. If the tank is $\frac{5}{6}$ full and all the three pipes are opened together, then in how many hours will the tank be emptied?

Option 1: $10 \frac{1}{2}$

Option 2: $12 \frac{1}{2}$

Option 3: $10$

Option 4: $12$

Question : Pipe P alone can fill a tank in 18 hours and Pipe Q alone can fill the same tank in 24 hours. If both the pipes are opened on alternate hours one at a time and pipe Q is opened for the first hour, then in how much time the tank will be full?

Option 1: $\frac{64}{5}$ hours

Option 2: $\frac{78}{5}$ hours

Option 3: $20$ hours

Option 4: $\frac{62}{3}$ hours

Question : 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, and then pipe A is opened. The time taken by the three pipes together to fill the remaining part of the tank is:

Option 1: $3\ \text{hours}$

Option 2: $2\ \text{hours}$

Option 3: $2\frac{1}{2}\ \text{hours}$

Option 4: $3\frac{1}{2}\ \text{hours}$

Question : Pipes A and B together can fill a tank in 10 hours. Pipes B and C together can fill the same tank in 12 hours. Pipes A and C together can fill the same tank in 15 hours. In how many hours can pipe B alone fill the same tank?

Option 1: $\frac{120}{7}$ hours

Option 2: $15$ hours

Option 3: $\frac{120}{11}$ hours

Option 4: $\frac{155}{13}$ hours

Question : Two taps P and Q can fill a tank alone in 10 hours and 12 hours respectively. If the two taps are opened at 9 a.m., then at what time should the tap P be closed to fill the tank at exactly 3 p.m.?

Option 1: 2 p.m.

Option 2: 1 p.m.

Option 3: 3 p.m.

Option 4: 12 p.m.