Question

Paulo tracks his commute time. The coordinate plane below shows some of his commute times in the last two weeks. The $x-$axis of the graph represents the number of days before today. For example, −1, would represent yesterday. The $y-$axis represents the commute time in minutes.


2 days ago, Paulo's commute time was halfway between his commute times 8 and 9 days ago.
At what coordinates should Paulo graph his commute time 2 days ago?

• A. (−2, 18)
• B. (−2, 16)
• C. (−2, 21)
• D. (−2, 24)

Answer 1

The correct option is C (−2, 21)

From the given coordinate plane,
Paulo's commute time was 18 minutes 9 days ago, and 24 minutes 8 days ago.
The difference is 24 − 18 = 6 minutes.


So, 2 days ago, the commute time was
$\frac{6}{2}$ = 3 minutes away from both (−2, 24) and (−2, 18).


As the $y-$axis represents minutes, 3 minutes away from both (−2, 24) and (−2, 18) is (−2, 21).
Paulo should graph his commute time 2 days ago at (−2, 21).