Answer :
Let us assume sea level is Zero, 0.
Don't forget the boat is 4 feet above sea level. Am thinking her measurements are taken from this reference.
So if she descends 28 feet down, that would be: 4 feet from the boat and 24 feet into the water.
+4 0 -24: From +4 to -24 is 28 feet.
The answer is -24. The minus is just a sign to show the reference is below the sea level.
Don't forget the boat is 4 feet above sea level. Am thinking her measurements are taken from this reference.
So if she descends 28 feet down, that would be: 4 feet from the boat and 24 feet into the water.
+4 0 -24: From +4 to -24 is 28 feet.
The answer is -24. The minus is just a sign to show the reference is below the sea level.