A tank is filled by one pipe in 8 hours and emptied by another in 12 hours. Time to fill when both operate?

One tap can fill a water tank in 3 hours and another tap can empty it in 4 hours. If the tank is one-third full and both the taps are opened together, then the time taken to fill the tank will be

Three taps A, B and C together can fill a tank in 6 hours. Tap C alone can fill the tank in 12 hours. To fill the tank, when it is empty, all the three taps are started together. After working t hour…

In the bottom of a water tank, there are two drains A and B. If only A is open, it takes 30 minutes to empty a full tank and if only B is open, it takes 20 minutes. If for 10 minutes both drains are…

Eight men and 24 women can finish a piece of work in one day while 12 men and 18 women can also finish it in one day. What is the time taken by 24 men and 72 women to finish the work?

Two persons A and B working together, can dig a trench in 8 hours, while A alone can dig it in 12 hours. In how many hours B alone can dig the same trench?