Question

or
Read this word problem.
A dolphin was swimming 7 meters below the surface of the ocean. It located a squid and dove down 4 more meters to eat it. What is the location of the dolphin now relative to the surface?
To solve the problem, Lamar subtracted
–
7–(
–
4) and came up with an answer of
–
3 meters. Is Lamar correct? Why or why not?

Answer 1

To determine whether Lamar is correct, we need to analyze the situation step by step.

1. The dolphin starts at a position of -7 meters (7 meters below the surface).
2. The dolphin then dives down an additional 4 meters. Since diving deeper means going further down into the negative values,
we can represent this as:
\[
-7 - 4 = -11 \text{ meters}
\]

So, after diving an additional 4 meters, the dolphin is now at -11 meters, meaning it is 11 meters below the surface.

Lamar's calculation was:
\[
-7 - (-4) = -7 + 4 = -3
\]
This simplification is incorrect because subtracting a negative (as he has done) does not apply in this context. The dolphin was not moving to a higher position; it was diving deeper into negative territory.

Therefore, Lamar is not correct. The correct final position of the dolphin relative to the surface is -11 meters.