Question : P alone can complete a work in 25 days and Q alone can complete the same work in 50 days. If both of them work together, then in 12 days what percent work of the total work will be completed?

Question : A alone can complete a work in 25 days and B alone can complete the same work in 50 days. If both of them work together, then in 9 days what percentage work of the total work will be completed?

Question : $\mathrm{N}_1$ alone can do 20% of a piece of work in 6 days, $\mathrm{N}_2$ alone can do 20% of the same work in 4 days, and $\mathrm{N}_3$ alone can do 50% of the same work in 12 days. In how many days can they complete the work, if all of them work together?

Question : X and Y together can do a work in 10 days. Y and Z together can do the same work in 15 days. Z and X together can do the same work in 12 days. In how many days can Z alone do the same work?

Question : A, B, and C together can complete a work in 5 days. A and B together can complete the same work in 6 days. C alone can finish the same work in how many days?