A group of workers can complete a job in 12 days. If they are joined by 4 more workers, they can complete the job in 8 days. How many workers were there originally?

480 persons working 10 hours per day complete one-fourth of a work in 10 days. How many additional persons are to be employed in order to complete the remaining work in 20 days, working 8 hours per d…

If 4 men or 6 women can do a piece of work in 12 days working 7 hours a day. How many days will it take to complete a work twice as large with 10 men and 3 women working together 8 hours a day?

If A and B can finish a work in 10 days, B and C can finish the same work in 12 days, C and A can finish the same work in 15 days; then in how many days can A, B and C together finish half of the wor…

10 women can complete a work in 7 days and 10 children take 14 days to complete the work. How many days will 5 women and 10 children take to complete the work?

A certain number of men can do a work in 60 days. If there were 8 more men, it could be finished in 10 days less. Number of men?