Two pipes A and B can fill a cistern in 12 minutes and 16 minutes respectively. If both the pipes are opened together, then after how much time B should be closed so that the tank is full in 9 minutes?

12 buckets of water fill a tank when the capacity of each tank is 13.5 litres. How many buckets will be needed to fill the same tank, if the capacity of each bucket is 9 litres?

9 examiners can examine a certain number of answer books in 12 days by working 5 hours a day. How many hours in a day should 4 examiners work to examine twice the number of answer books in 30 days?

A and B can do a work in 10 days. B and C in 12 days while C and A in 15 days. How long would they take if all the three work together?

30 laborers, working 7 hours a day can finish a piece of work in 18 days. If the laborers work 6 hours a day, then the number of laborers to finish the same piece of work in 30 days, will be:

A, B and C can do a piece of work in 11 days, 20 days and 55 days respectively, working alone. How soon can the work be done if A is assisted by B and C on alternate days?

A tap can fill a tank in 16 minutes and another can empty it in 8 minutes. If the tank is already half full and both the tanks are opened together the tank will be:

A can do a piece of work in 10 days; B in 15 days. They work for 5 days. The rest of the work was finished by C in 2 days. If they get Rs. 1500 for the work, the daily wages of B and C are:

A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in:

A 210m long train takes 6s to cross a man running at 9 kmph in a direction opposite to that of the train. What is the speed of the train? (in kmph)