A set of 10 new questions in each round Question: ( 1 of 10 ) If Robert can finish the work in 4 days and David can finish the same work in 7 days, then in how many days both can finish the work together? (A) 4 6/11 days or 4.545 days (B) 5.5 days (C) 2 6/11 days or 2.545 days (D) 11 days