A1 Jana leaves school on rollers. First, she rolls $3 \mathrm{~km}$ west, then $1 \mathrm{~km}$ south, $3 \mathrm{~km}$ east, and $1 \mathrm{~km}$ south. How far and in which direction must she travel to return to school by the shortest path?
(A) $2 \mathrm{~km}$ north
(B) $2 \mathrm{~km}$ south
(C) $2 \mathrm{~m}$ east
(D) $2 \mathrm{~km}$ west
(E) Cannot be determined.

![](https://cdn.mathpix.com/cropped/2024_06_07_7bf2b29f7493f2ef25deg-2.jpg?height=311&width=323&top_left_y=758&top_left_x=1620)
A1 In the network, we draw the initial point. From this point, 3 units left, 1 unit down, 3 units right, and 1 unit down to the final point. From the final point to the initial point, we come by 2 units up or $2 \mathrm{~km}$ north.