A and B can do a work in 20 days, B and C in 40 days and A and C in 30 days. Who is the most efficient among the the three perosn?

A and B can complete a work in 40 days, B and C in 60 days and A and C is 48 days. Who is the most efficient worker among A, B and C?

A and B can do a work in 8 days, B and C in 12 days, and A and C in 16 days. In what time can they do it, all working together ?

A and B together can do work in 20 days, B and and C and do the same work in 60 days. Who is the most efficient among A,B and C?

A and B can do a piece of work in 10 days, B and C in 15 days and C and A in 20 days. C alone can do the work in :

A and B can do a piece of work in 12 days, B and C in 15 days and A and C in 20 days. In how many days can each alone do the work?

A and B can do a job in 12 days, B and C in 15 days and C and A in 20 days. How long would A take to do that work?

A and B can finish a work in 12 days, B and C in 15 days and A and C in 20 days. In how many days would A along finish the work? (A) 20 (B) 30 (C) 40 (D) 60