The rates of working of A and B are in the ratio 3:4.The number of days taken by them to finish the work are in the ratio

The rates of working of two tapes A and B are in the ratio 2:3. The ratio of the time taken by A and B respectively to fill a given cistern is

A is thrice as good a workman as B and takes 10 days less to do a piece of work than B takes. The number of days taken by B to finish the work is :

If a work can be completed by A in 30 days and by B in 60 days. Then, the number of days taken by them to complete the work, working together is