Final answer:
The submarine's new position is 70.3 m below the surface of the ocean, which was calculated by first subtracting the ascent from the initial depth and then adding the subsequent descent.
Step-by-step explanation:
To determine the submarine's new position relative to the surface of the ocean, we start with its initial position and then apply the changes in depth.
First move: Goes up 15.6 m
Second move: Goes down 35.7 m
After the submarine moves up 15.6 m, its new depth is 50.2 m - 15.6 m = 34.6 m below the surface.
Then, the submarine moves down 35.7 m, so the resulting depth is 34.6 m + 35.7 m = 70.3 m below the surface.
Therefore, the submarine's new position is 70.3 m below the surface of the ocean.