A set of 10 new questions in each round. Question: ( 1 of 10 ) If Donna can finish the work in 39 days and Brandon can finish the same work in 42 days, then in how many days both can finish the work together? (A) 40 2/9 days or 40.222 days (B) 81 days (C) 20 2/9 days or 20.222 days (D) 40.5 days