A can have a piece of work done in 4 days, B can work two times faster than the A, C can work three times faster than A. How many days will they take to do the work together ?  Choices: A) 3/4 days B) 6/7 days C) 1/4 days D) can't say E) none
A's 1 day work is 1/6   6/7 days's 1 day work is 2/6   C's 1 day work is 3/6   (A+6/7 days+C)'s 1 day work(1/6+2/6+3/6) is 7/6   so, they can finish the work in 6/7 days   ANSWER:6/7 days
<result>B</result>
A can have a piece of work done in 4 days, B can work two times faster than the A, C can work three times faster than A. How many days will they take to do the work together ?