Question

Tomas works as an underwater photographer. He starts at a position that is 17 feet below sea level. He rises 8 feet, then descends 13 feet to take a photo of the coral reef. Enter and expression to find his position relative to sea level when he took the photo and evaluate the expression.

Answer 1

-22

Explanation:

-17 + 8 = -9

-9 - 13 = -22

Answer 2

-17 +8 -13 = -22 (22 ft below sea level)

Explanation:

-17 +8 -13 = -22

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You can consider the problem to be represented by a number line with feet above sea level on the right, and feet below sea level on the left. The number 0 represents sea level.

Then 17 feet below sea level corresponds to -17 on the number line.

Rising 8 feet corresponds to adding 8 to the number on the number line.

Descending 13 feet corresponds to subtracting 13 from the number on the number line.

Together, these operations amount to ...

-17 +8 -13

The ending position is -22 on the number line.

Tomas took the photo at 22 feet below sea level.