Anil alone takes 2 hours 40 minutes to complete a work and Sumit alone can complete the same work in half of the time taken by Anil. How much time will be taken by Sumit alone to complete the work?

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?