Answer:
5.3 meters
Explanation:
They kind of worded the question weirdly, but let's give it a shot. Apologies if it's wrong.
So the dolphins jumps 4.5m above the surface of the water.
The surface of the water is 0m
The friend swims 9.8m directly below her
So in order to find the friends location relative to the surface, we wouldn't do 0-9.8, we would do 4.5-9.8
4.5 - 9.8 = -5.3 meters