A set of 10 new questions in each round Question: ( 1 of 10 ) William can finish a work in 15 days. Joseph can finish the same work in 20 days while Thomas can finish the work in 25 days. How long will it take to finish it if they work together? (A) 15 days (B) 6 18/47 days or 6.383 days (C) 12 18/47 days or 12.383 days (D) 20 days