A set of 10 new questions in each round. Question: ( 1 of 10 ) Christopher can finish a work in 25 days. Matthew can finish the same work in 30 days while Anthony can finish the work in 35 days. How long will it take to finish it if they work together? (A) 18 87/107 days or 18.813 days (B) 22.5 days (C) 9 87/107 days or 9.813 days (D) 30 days