A, B and C can do a piece of work in 6,8 and 12 days respectively. In how many days would all of them complete the same job working together? Choose the correct choice from the following options
A) 2 3/4 days.  B) 2 2/3 days.  C) 2 3/2 days.  D) 3 1/2 days.  E) 3 3/4 days.
Explanation:   In this type of questions we first get the finishing of work in 1 day for A,B,C then we will add them to get the result, as:   Part finished by A in 1 day= 1/6   Part finished by B in 1 day = 1/8   Part finished by C in 1 day =1/12   Part finished by (A+B+C) in 1 day = 9/24   = 9/24 Remaining work =1-9/20=11/20. Number days to finish the work by A+B+C =2 2/3 days.   Option 2 2/3 days.
<result>B</result>
A, B and C can do a piece of work in 6,8 and 12 days respectively. In how many days would all of them complete the same job working together?