Abel can complete a work in 8 days, Ben in 12 days and Carla in 15 days. All of them began the work together, but Abel had to leave after 2 days and Ben 3 days before the completion of the work. How long did the work last? Pick one: A) 4 B) 7 C) 8 D) 9 E) 10
Abel in the 2 days that he worked completed 1/4 of the job = 3/4 remains   Then if Ben had to leave 3 days before the completion, this means that Carla had to work alone for these 3 days in which she completed 1/5 of the job.   Now together, Ben and Carla completed the job in (1/12 + 1/15)(t) = 3/20   3/20 (t) = 3/20 ---&gt; t = 1   Therefore, these 1 day worked plus the 3 days that Carla had to work by herself add to 4 days   4nswer: 4
<result>A</result>
Abel can complete a work in 8 days, Ben in 12 days and Carla in 15 days. All of them began the work together, but Abel had to leave after 2 days and Ben 3 days before the completion of the work. How long did the work last?