Answer: 48 feet below the surface
Explanation:
From the question, we are informed that two divers are underwater. Nick is 33 feet below the surface while Tristan is 15 feet above him.
Tristan's depth will be represented as x.
Therefore, x - 33 = 15
x = 15 + 33
x = 48
Therefore, the answer is 48 feet below the surface.