P alone can complete a work in 15 days. Q and R together can complete the same work in 12 days, and R alone can do it in 20 days. If they all work together to complete the work and the total wage is Rs. 4500, find the value of (x + 350) where x is the difference between the wages obtained by P and R.

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?