Question

A scuba diver dove 63 feet below the ocean's surface. He then ascended 27 feet to under an underwater cave. What is the depth of the entrance of the cave?

Answer 1

First, we need to define a zero in the vertical position.

Let's define the zero as the ocean's surface.

"A scuba diver dove 63 feet below the ocean's surface."

Then the scuba's position at this moment was:

P = -63ft

"He then ascended 27 feet to under an underwater cave."

The new position will be:

P = -63ft + 27ft = -36ft

And here is the entrance of the underwater cave.

Then we can conclude that the depth of the entrance of the underwater cave is 36ft deep, or that the entrance is 36ft below the ocean's surface.