Question : A₁, A₂, and A₃ alone can complete a piece of work in 12 hours, 24 hours, and 16 hours respectively. Working together, in how much time will they complete the same work?

Question : A and B together can finish a work in 7.2 hours. If B alone can finish the same work in 18 hours, then A alone can do it in:

Question : P alone can do a piece of work in 24 days. Q alone can do it in 30 days and R alone can do it in 20 days. In how many days they can complete it together?

Question : A alone can do $\frac{1}{10}$th part of a work in 8 hours. B alone can do $\frac{1}{5}$th part of the same work in 4 hours. If they work together, then how many hours will they take to complete $\frac{9}{16}$th part of the same 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.