A can complete a work in 18 hours and B can complete the same work in half of his time. If they start working together then how much part will the complete in one day?

A can complete a piece of work in 18 days and B can complete the same work in half time taken by A. Then, working together, what part of the same work they can complete in a day?

A can complete a work in 20 days & B can complete the same work in 25 days. If they start the work together but After 5 days A left the work . In how many days the total work would be finished ?

A can complete a work in 12 days and B complete the same work in 15 days. Find the time taken by them when A and B worked together.