A can do a piece of work in 4 hours; B and C together can do it in 3 hours, which A and B together can do it in 2 hours. How long will C alone take to do it?
Choices
A) 12hours	B) 10hours	C) 6hours	D) 8hours	E) 4hours
A's 1 hour work = 1/4;   (B + C)'s 1 hour work = 1/3;   (A + B)'s 1 hour work = 1/2   (A + B + C)'s 1 hour work = (1/4 + 1/3) = 7/12   C's 1 hour work = (7/12 - 1/2) = 1/12   C alone will take 12 hours to do the work.   12hoursnswer:12hours
<result>A</result>
A can do a piece of work in 4 hours; B and C together can do it in 3 hours, which A and B together can do it in 2 hours. How long will C alone take to do it?