Anjani can do a certain piece of work in 24 days. Anjani and Khushbu can together do the same work in 12 days, and Anjani, Khushbu and Sushmita can do the same work together in 9 days. In how many days can Anjani and Sushmita do the same work together?

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?