Let the street seller starts from his home at point A. He pushes his cart 1 km East, then he turns North and walks 4 km to reach C, then he turns West and walks 9 km to reach D, then he turns to his left and walks 4 km southwards to finally stop at point E.
⇒ AE=9−1=8 km ∴ He is 8 km west with respect to his home.