Honey and Junnu together can finish a certain work in 20 days. Honey having worked for 12 days, Junnu finished the remaining work alone in 36 days. In how many days can Junnu finish the whole work alone?

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?