A can do a piece of work in 14 days which B can do in 21 days. They begin together but 3 days before the completion of the work. A leaves off. The total number of days to complete the work is ?

A can do a piece of work in 14 days which B can do in 21 days. They be

1.	A can do a piece of work in 14 days which B can do in 21 days. They begin together but 3 days before the completion of the work. A leaves off. The total number of days to complete the work is ?
A.	${\text{6}}\frac{3}{5}$$
B.	${\text{8}}\frac{1}{2}$$
C.	${\text{10}}\frac{1}{5}$$
D.	${\text{13}}\frac{1}{2}$$
Answer» D. ${\text{13}}\frac{1}{2}$$