A can do a piece of work in 10 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?	Choose the correct choice.
A) 15 days
B) 10 days
C) 12 days
D) 19 days
E) 13 days
10 days   (x â€“ 5)/10 + x/20 = 1   x = 10 days
<result>B</result>
A can do a piece of work in 10 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?