Answer:
The person in the opposite direction is at -20 feet from sea level.
Step-by-step explanation:
We know that Susan is at 20 feet above sea level.
So, the person located at the same distance from sea level but in the opposite direction, is actually located at -20 feet from sea level.
Remember that opposite direction refers to opposite sign of the magnitude, when we talk about vectorial magnitudes, signs indicate orientation.
