Answer:
The action required by the submarine to get back to the surface is to rise 195 feet
Step-by-step explanation:
we know that
The ocean's surface or sea level is at an elevation of 0 feet.
we have
1) A submarine dives 270 feet below the ocean's surface
In this moment the position of the submarine is
-270 ft ---> is negative because is below the sea level
2) It then rises 90 feet
In this moment the position of the submarine is
-270+90=-180 feet
3) rises another 40 feet,
In this moment the position of the submarine is
-180+40=-140 feet
4) Finally dives 55 feet
In this moment the position of the submarine is
-140-55=-195 feet
therefore
The action required by the submarine to get back to the surface is to rise 195 feet
