Question

A deep-sea diver explores fish at an elevation of -20.5 feet. Then the diver descends 60.5 feet the elevation of the top of the coral reef. What is the elevation of the top of the Coral reef?

Answer 1

If he descends 60.5 feet from the top of the reef, then the elevation to the top of the reef is 60.5 feet

Answer 2

This problem can be solved simply by subtracting 60.5 from -20.5 because the diver started at -20.5 ft and then descended another 60.5 ft.  Since, we are subtracting a number from a negative number, that means that the answer will too be negative.

-20.5-60.5=-81

The elevation of the top of the coral reef is -81 ft.

Hope this helps!