A set of 10 new questions in each round. Question: ( 1 of 10 ) Donald can finish a work in 35 days. Paul can finish the same work in 40 days while Andrew can finish the work in 45 days. How long will it take to finish it if they work together? (A) 40 days (B) 26 37/191 days or 26.194 days (C) 13 37/191 days or 13.194 days (D) 30 days