A wheel that has 6 cogs is meshed with a larger wheel of 14 cogs. When the smaller wheel has made 21 revolutions, then the number of revolutions made by the larger wheel is?

If A can complete a work in 30 days and B can complete the same work in 20 days, then in how many days will A and B together complete the same work?

A town with a population of 2000 has provisions for 30 days.  After 10 days, 500 more men are added. How long will the food last at the same rate?

A is thrice as fast as B and is therefore able to finish a work in 60 days less than B. The time in which they can do it working together is:

A man digs a trench in 3 days, another man can dig it in 5 days and a third man can dig it in 6 days working alone. How much time will they take to dig it together?

If four evaluators can examine a certain number of answer books in 8 days  by working 5 hours a day, then for how many hours a day would two evaluators have to work in order to examine twice the number of answer books in 20 days?

A and B together can complete a work in 3 days. They start together. But, after 2 days, B left the work. If the work is completed after 2 more days, B alone could do the work in

A & B can complete a piece of work in 12 days, B & C can complete it in 14 days and C & A can complete it in 18 days. In how many days will they complete it together?

A man is twice as fast as a woman and a woman is twice as fast as a boy. If all of them i.e. a man, a woman and a boy can finish together in 4 days, in how many days a boy shall do it alone?

A mother is 3 times efficient than her daughter. If the daughter completes a piece of work in 15 days, how long will it take for both mother and daughter to complete the same work?