He picks up some excess dirt at (8, 19) and then maneuvers through the job site along the vectors (-4,0) ,(2,8) ,(8,10) to get to the spot to unload the dirt.
The starting point is (8, 19)
He move along the vector (-4,0) lands at
(8-4, 19+0) = (4, 19)
Then he starts at (4,19) and move along the vector (2,8) lands at
(4+2, 19+8) = (6, 27).
Then he starts at (6,27) and move along the vector (8,10) lands at
(6+8, 27+10) = (14, 37).
The unloading point is (14, 37).
A single vector from the loading point to the unloading point is
(14, 37) - (8, 19) = (6, 18)