Question

An airplane flies six hundred miles to the south; then, after landing and refueling, it flies due north for three hundred miles. What is the airplane's displacement? (Remember, displacement is a vector, so direction needs to be indicated in your answer).

Answer 1

If it's going 600 miles S, and 300 miles N, the displacement is 300 miles S

Answer 2

Displacement =

     (distance between the start-point and the end-point)
in the direction of
     (direction from the start-point to the end-point).

For the entire story, the displacement is

                         300 miles south .