If 81 students can do a painting on a wall of length 448 m in 56 days. How many students can do the painting on a similar type of wall of length 160 m in 27 days?

A and B together can do a piece of work in 16 days and A alone can do it in 48 days. How long will B done take to complete the work?

A works 3 times as fast as B and is able to complete a task in 24 days less than the days taken by B. Find the time in which they can complete the work together.

P and Q can do a piece of work in 20 days and 30 days respectively. They started the work together and Q left after some days of work and P finished the remaining work in 5 days. After how many days from the start did Q leave?

A and B can do a piece of work in 12 days and 9 days respectively. They work on alternate days starting with A on the first day. In how many days will the work be completed?