A can do a piece of work in 15 days and B in 20 days. They began the work together but 5 days before the completion of the work, A leaves. The work was completed in?  Pick: A) 8 days B) 10 days C) 15 days D) 11 3/7 days E) 16 days
Explanation:   (x – 5)/15 + x/20 = 1   x = 11 3/7 days   Answer: 11 3/7 days
<result>D</result>
A can do a piece of work in 15 days and B in 20 days. They began the work together but 5 days before the completion of the work, A leaves. The work was completed in?