Answer: Elevation after the dives is -28 feet
A divers elevation is -10 feet relative to the sea level
She dives down 18 feet
Her elevation after the dives can be calculated as
The 18 feet will be negative because she is diving down the sea level. This means she is going below
-10 + (-18) = -10 - 18
Elevation after the dive = -28 feet
The answer is - 28 feet