How far from and on which side of Okemos road did it start?

Question

A car travels along a straight north-south road. A coordinate system is established on the road, with x increasing to the north. The car ends up 14 mi south of the intersection with Okemos Road. If its displacement was -23 mi, how far from and on which side of Okemos Road did it start?

Answer 1

In this problem, +x = to the north and -x = to the south. The total displacement is -23 mi, which means that altogether the car traveled 23 miles to the south in its trip. Wherever the car ended up, it started at a location 23 miles to the north. If the car ended up 14 mi south of the intersection with Okemos Road, then it started 23 miles north of this location, or 9 miles to the north of the intersection with Okemos Road.