Three years ago, the residents of Planet $X$ found a black hole leading to another galaxy. Since then, they have been leaving Planet $X$ at a rate of $120$ residents per year. $\newline$ The following equation describes this situation: $\newline$ $-120 \cdot 3=-360$ $\newline$ What does $-360$ tell us? $\newline$ Choose $1$ answer: $\newline$ (A) A total of $360$ residents left Planet $X$ in the past $3$ years. $\newline$ (B) $360$ residents left Planet $X$ each year. $\newline$ (C) There are $360$ residents left on Planet X.

Full solution

Q. Three years ago, the residents of Planet

X

found a black hole leading to another galaxy. Since then, they have been leaving Planet

X

at a rate of

120

residents per year.

\newline

The following equation describes this situation:

\newline

-120 \cdot 3=-360

\newline

What does

-360

tell us?

\newline

Choose

1

answer:

\newline

(A) A total of

360

residents left Planet

X

in the past

3

years.

\newline

(B)

360

residents left Planet

X

each year.

\newline

360

residents left on Planet X.

Breakdown of Equation: The equation given is $-120\times3=-360$ . Let's break it down. $\newline$ $-120$ represents the rate at which residents are leaving Planet X per year. $\newline$ $3$ represents the number of years that have passed. $\newline$ Multiplying these together gives us the total number of residents that have left.
Calculation of Total Residents Leaving: Now, let's do the calculation: $-120$ multiplied by $3$ equals $-360$ . This means that over the course of $3$ years, a total of $360$ residents have left Planet X.
Verification of Total Residents Leaving: So, $-360$ tells us the total number of residents that left Planet X over the past $3$ years. $\newline$ This matches with option $(A)$ and not with $(B)$ or $(C)$ .