I can complete a book in `30` days.The part of the book that I can complete in `20` days

U, V and W together can complete a work in 10 days. If U alone can complete the work in 20 days and V alone can complete the work in 30 days, then in how many days W alone can complete the work?

A and B can complete a task in 30 days, whereas A,B and C can complete the same task in 21 days. In how many days can C alone complete the task?

In how many days will B alone complete the work? I. A and B together can complete the work in 8 days. II. B and C together can complete the work in 10 days. III. A and C together can complete the work in 12 days

24 men can complete a job in 20 days. The number of men required to complete the job in 16 days is :

A and B can complete a task in 30 days, whereas A. B and C can complete the same task in 21 days. In how many days can C alone complete the task?

A alone can complete a work in 10 days and B alone can complete the same work in 20 days. In how many days both 4 and B together can complete half of the total work?

X, Y and Z together can complete a work in 20 days. Y and Z can complete the same work in 30 days. In how many days X alone can complete the same work?

C alone can complete a work in 20 days and D alone can complete the same workin 30 days. In how many days C and D together can complete the same work?