Question

Students were asked to find the difference between the positions of two sea creatures. An octopus was positioned at 180 feet below sea level. A narwhal was swimming 7 feet below sea level. Demarcus said you can find the difference with this expression: -7-(-180), Maria said you can find the difference with this expression: -180-7. Who was correct, and why? What is the difference between the positions of the two sea creatures?

A) Demarcus was correct; the difference is 173 feet.
B) Maria was correct; the difference is 187 feet.
C) Demarcus was correct; the difference is -173 feet.
D) Maria was correct; the difference is -187 feet.

Answer 1

Demarcus's expression is correct as it accounts for the subtraction of a negative number. The difference between the positions of the octopus and the narwhal is 173 feet.

Step-by-step explanation:

The student seeks to find the difference in position between two sea creatures, an octopus and a narwhal. Demarcus's expression for finding the difference is -7-(-180), which is correct because it properly takes into account the subtraction of a negative number, representing depth below sea level. The expression essentially adds the absolute values of the depths. On the other hand, Maria's expression of -180-7 implies that the narwhal is further below the octopus, which is incorrect.

Performing the calculation for Demarcus's expression gives us:

-7 - (-180) = -7 + 180 = 173 feet.

Therefore, the correct answer is that Demarcus was right, and the difference between the positions of the two sea creatures is 173 feet.