Question : P and Q can do a piece of work in 14 days. Q and R together can do it in 21 days. If P is twice as good a workman as R, then in how many days Q alone can do the work?

Question : P and Q can do a work together in 30 days. Q and R can do the same work together in 24 days and R and P together in 20 days. They started the work together, but Q and R left after 10 days. How many more days will P take to finish the remaining work?

Question : U, V, and W together can complete a work in 10 days. If U can work thrice as fast as V and V can work twice as fast as W, then in how many days W alone can complete the same work?

Question : P and Q can do a piece of work in 24 days, while R and S can do the same work in 8 days. In how many days P, Q, R, and S do it together?

Question : P, Q and R together can complete a work in 40 days. P and Q together can complete the same work in 90 days. Then R alone can complete the same work in how many days?