The figure below shows the velocity field for the Gulf Stream.
The vectors are shown on the graph at intervals of 30 km (thus, the first, very small, vector at the bottom-left of the figure is at the point $(0,0)$, and the vector immediately to the right of that is at $(30,0)$, etc.).

For each of the following tables of velocity vectors (velocities given in cm/sec) give the coordinates of the point on the velocity field corresponding to the center vector in the table.

(a)

$-88\vec i-42\vec j$	$-93\vec i+44\vec j$	$-31\vec i+39\vec j$
$-41\vec i-73\vec j$	$-8\vec i+38\vec j$	$-11\vec i+69\vec j$
$77\vec i-51\vec j$	$91\vec i+35\vec j$	$28\vec i+40\vec j$

The vector $-8\vec i+38\vec j$ is at the point
(Give an (x,y) ordered pair.)

(b)

$-15\vec i-13\vec j$	$-86\vec i-41\vec j$	$-123\vec i-33\vec j$
$-29\vec i-54\vec j$	$-95\vec i-111\vec j$	$-83\vec i-44\vec j$
$-10\vec i-78\vec j$	$-13\vec i-94\vec j$	$-27\vec i-34\vec j$

The vector $-95\vec i-111\vec j$ is at the point
(Give an (x,y) ordered pair.)