Abel can complete a work in 10 days, Ben in 12 days and Carla in 16 days. All of them began the work together, but Abel had to leave after 2 days and Ben 4 days before the completion of the work. How long did the work last? Choose the most appropriate option
A) 6  B) 7  C) 7 2/3  D) 9  E) 10
Abel in the 2 days that he worked completed 1/5 of the job = 4/5 remains   Then if Ben had to leave 4 days before the completion, this means that Carla had to work alone for these 4 days in which she completed 1/4 of the job.   Now together, Ben and 7 2/3arla completed the job in (1/12 + 1/15)(t) = 11/20   3/20 (t) = 11/20 ---&gt; t = 3 2/3   Therefore, these 3 2/3 days worked plus the 4 days that 7 2/3arla had to work by herself add to 7 2/3 days   Answer: 7 2/3
<result>C</result>
Abel can complete a work in 10 days, Ben in 12 days and Carla in 16 days. All of them began the work together, but Abel had to leave after 2 days and Ben 4 days before the completion of the work. How long did the work last?