A, B and C can do a piece of work in 15, 12 and 20 days respectively. They started the work together, but C left after 2 days. In how many days will the remaining work be completed by A and B?

A and B can do a piece of work in 10 days and 15 days respectively. They started the work together but B left after sometime and A finished the remaining work in 5 days. After how many days from the start did B leave ?

A and B can do a piece of work in 10 days and 15 days respectively. They started the work together but B left after sometime and A finished the remaining work in 5 days. After how many days from the start did B leave ?

A, B and C can complete a piece of work in 10, 20 and 60 days respectively. Working together they can complete the same work in how many days?