A can do a piece of work in 4 hours; B and C together can do it in 3 hours, while 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 answers.
A) 12 B) 9 C) 8 D) 6 E) 5
A's 1 hour's work = 1 ;   4   (B + C)'s 1 hour's work = 1 ;   3   (A + C)'s 1 hour's work = 1 .   2   (A + B + C)'s 1 hour's work = ( 1 + 1 ) = 7 .   4 3 12   B's 1 hour's work = ( 7 - 1 ) = 1 .   12 2 12   Therefore 12 alone will take 12 hours to do the work.
<result>A</result>
A can do a piece of work in 4 hours; B and C together can do it in 3 hours, while A and C together can do it in 2 hours. How long will B alone take to do it?