Question : S alone can do a piece of work in 14 days. T alone can do the same work in 21 days. U alone can do the same work in 28 days. Working together, in how many days will they complete the work?

Question : A alone can do a piece of work in 7 days, while B alone can do it in 10 days. In how many days will they complete the same work if they both work together?

Question : A alone can do $\frac{1}{4}$th part of the work in 12 days. B alone can do $\frac{1}{5}$th part of the work in 4 days. In how many days can A and B together can do the same work?

Question : Riya alone can complete a piece of work in 6 days while Siya alone can do the same work in 9 days. If they both work together, then how many days will be required to finish the work?

Question : A piece of work can be completed by P and Q together in 24 days, and the same piece of work can be completed by R alone in 60 days. If P and R together can do the same work in 36 days, then find the time taken by Q to complete this piece of work alone.