Question : Tap A can fill an empty tank in 8 hours if no other tap is open, and tap B can empty the same tank, when filled, in 12 hours, when no other tap is open. Find the time taken to fill the same tank, when empty, if both the taps are opened together.

Question : Two pipes can fill a tank alone in 20 hours and 24 hours respectively and an outlet pipe alone can empty 20 gallons of water per hour. All three pipes working together can fill the same empty tank in 40 hours. What is the capacity of the tank?

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.?

Question : If $\frac{J}{4}=\frac{K}{5}=\frac{L}{3}$, what is the value of $(L + J)^2:(J +K)^2:(K +L)^2$?

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?