Question

An elevator moving down passes its neighbor, an elevator moving up. Their speed relative to one another is 8 m/s. What is the velocity of each elevator relative to someone standing on the first floor? Assume that the elevators are traveling at the same speed, and that the upward direction is positive.

Answer 1

The person standing still would see the elevator move at 4 m/s, because if the elevators are moving in opposite directions at 4 m/s each then for each other it would look like 8 m/s

Answer 2

4 m/s. 

i hope this helps!