x men working x hours per day can do x units of a work in x days. How much work can be completed by y men working y hours per day in y days?

If 18 binders bind 900 books in 10 days, how many  binders will be required to bind 660 books in 12 days?

A tank is filled in 5 hours by theree pipes A, B and C. The pipe C is twice as fast as B and B is twice as fast as A. How much time will pipe A alone take to fill the tank ?

A can lay railway track between two given stations in 16 days and B can do the same job in 12 days. With the help of C, they did the job in 4 days only. Then, C alone can do the job in:

A and B can do a piece of work in 72 days; B and C can do it in 120 days; A and C can do it 90 days. In what time can A alone do it?

12 years ago the ratio between the ages of A and B was 3 : 4 respectively. The present age of A is 3 3/4 times of C's present age. If C's present age is 10 Years, then what is B's present age? (in years)

Pipes A and B fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in

A pump can fill a tank with water in 2 hours. Because of a leak, it tookhours to fill the tank. The leak can drain all the water of the tank in:

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:

Two pipes A and B can fill a tank in 12 minutes and 15 minutes respectively. If both the taps are opened simultaneously, and the tap A is closed after 3 minutes, then how much more time will it take to fill the tank by tap B?