B takes three times as long as A and C together, and C takes twice as long as A and B together to do a certain job. If all three men working together can complete that work in 8 days, then A alone can finish that work in:

If P and Q together can complete a piece of work in 15 days and P alone can do it in 45 days, in how many days can Q alone complete that work?

A can lay a railway track between two stations in 16 days and B can do the same job in 12 days. With the help of C, they finished the job in 4 days. In how many days can C alone do the job?