A can do a piece of work in 4 hours; B and C together can do it in 2 hours, which A and C together can do it in 2 hours. How long will B alone take to do it? Choose the correct choice from the following: A) 2hours B) 3hours C) 4hours D) 5hours E) 6hours
A's 1 hour work = 1/4;   (B + C)'s 1 hour work = 1/2;   (A + C)'s 1 hour work = 1/2   (A + B + C)'s 1 hour work = (1/4 + 1/2) = 3/4   B's 1 hour work = (3/4 - 1/2) = 1/4   B alone will take 4 hours to do the work.   Answer:4hours
<result>C</result>
A can do a piece of work in 4 hours; B and C together can do it in 2 hours, which A and C together can do it in 2 hours. How long will B alone take to do it?