12 men can do a piece of work in 10 days while 9 women can do the same work in 20 days. If 3 men start working and work for 'T' days, and after that 3 women join them and together they take 6 more days to finish the remaining work, then what is the value of 'T'?

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?