X and Y can do a piece of work in 20 days and 12 days respectively. X started the work alone and then after 4 days Y joined him until the completion of the work. How long did the work last?

A can do work in 20 days. Then, he is assisted by B to complete the remaining work in 12 days. In how much time can B alone do the work?

A, B and C can do a piece of work in 20, 30 and 40 days, respectively. A and C started the work and B joined 4 days later. A left 8 days before the completion of work and C was also absent for 5 days in between. How many days will it take for the work to be completed?

X can do a piece of work in 8 days, Y can do it in 10 days and Z can do it in 20 days. In how many days can X, Y and Z together complete the work?

A can do a piece of work in 8 days and B can do the same work in 10 days. They started the work together but after 3 days, A left . In how many days B can complete the remaining work?

X, Y and Z can complete a job in 10 days, 12 days, and 15 days respectively. They started working together and after some days, Y left. The remaining work was completed by X and Z. A total of ₹24,000 were paid as wages to the three. The wages paid to X were ₹8,000 more than those paid to Y. After how many days did Y leave?