A and B can together finish a piece of work in 30 days. They worked on it 20 days and then B left. The remaining work was done by A alone in 20 days. A alone can finish the work in = ?

A and B can together finish a piece of work in 30 days. They worked on

1.	A and B can together finish a piece of work in 30 days. They worked on it 20 days and then B left. The remaining work was done by A alone in 20 days. A alone can finish the work in = ?
A.	0 days
B.	4 days
C.	8 days
D.	0 days
Answer» B. 4 days