Explanation:
At the elevation 617.5 feet below the sea level temperature of the water was °F
Explanation:
At 502.5 feet below the sea level temperature of the water is °F
When submarine dives down 115 feet deeper, water temperature drops by °F
Elevation after the submarine dove = -502.5 - 115 = -617.5 feet
This negative sign represents the elevation below the sea level.
And the temperature will be = 
= 
= 
= 
= °F
Therefore, at the elevation 617.5 feet below the sea level temperature of the water was °F
Hope it will help you.....