Abel can complete a work in 10 days, Ben in 12 days and Carla in 15 days. All of them began the work together, but Abel had to leave after 3 days and Ben 4 days before the completion of the work. How long did the work last? Choose the correct option: A) 6 8/9 B) 7 C) 8 D) 9 E) 10
Abel in the 3 days that he worked completed 3/10 of the job = 7/10 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 4/15 of the job.   Now together, Ben and Carla completed the job in (1/12 + 1/15)(t) = 13/30   3/20 (t) = 13/30 ---&gt; t = 26/9=2 8/9   Therefore, these 2 8/9 days worked plus the 4 days that Carla had to work by herself add to 6 8/9 days   6 8/9nswer: 6 8/9
<result>A</result>
Abel can complete a work in 10 days, Ben in 12 days and Carla in 15 days. All of them began the work together, but Abel had to leave after 3 days and Ben 4 days before the completion of the work. How long did the work last?