A set of 10 new questions in each round Question: ( 1 of 10 ) Anthony can finish a work in 27 days. Mark can finish the same work in 28 days while Donald can finish the work in 29 days. How long will it take to finish it if they work together? (A) 21 days (B) 28 days (C) 9 765/2351 days or 9.325 days (D) 18 765/2351 days or 18.325 days