Abraham can complete a work in 9 days, while Andrew can complete the same work in 6 days. In how many days can they complete the work if they work together?

A, B and C can finish a work in 15 days working alternately in the same order. The efficiency of A is the same as that of B, and the efficiency of C is equal to that of A. In how many days will the work be finished if they work alternately in the order C, A and B?

15 men complete a work in 10 days. 15 women complete the same work in 12 days. If all these men and women work together, then the number of days required to complete that work is:

Ramesh alone can complete a work in 24 days. Ramesh and Somesh can complete it in 8 days. How long will Somesh alone take to complete the work?