A can do a work in 20 days and B can complete the work in 25 days. C alone

A can do a piece of work in 20 days and B can do same work in 25 days. Both A and B start the work and after 8 days A left. In how many days will the total work be completed ?

A and B can do a work in 12 days, Band C can do the same work in 15 days, C and A can do the same work in 20 days. The time taken by A, B and C to do the same work is

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?

A alone can complete a work in 12 days and B alone can complete the same work in 24 days. In how many days can A and B together complete the same work?