If Roger can do a piece of work in 8 days and Antony can complete the same work in 5 days, in how many days will both of them together compete it?

A alone can complete a piece of work in 6 days and B alone can complete the same piece of work in 12 days. In how many days can A and B together complete the same piece of work ?

A can do a piece of work in 16 days and B can do the same work in 20 days.In how many days can they do the same work,working together?

A alone can complete a work in 6 days and B alone can complete the same work in 8 days. In how many days both A and B together can complete the same work?

A and B together can complete a piece of work in 4 days. If A alone can complete the same work in 12 days, in how many days can B alone complete that work ?

P can do a piece of work in 25 days and Q can do the same work in 15 days. In how many days they can complete the work by working together?