From the graph, the horizontal axis represents:
t= " hours after 7:00 a.m. "
The vertical axis represents:
" estimated wait time in minutes "
Point Ais approximately at:
A=(5,88.3)
Point Bis approximately at:
B=(9,65)
The average rate of change from point Ato point Bis calculated using:
(y_2-y_1)/(x_2-x_1 )
Substitute the values:
(65-88.3)/(9-5)
=(-23.3)/4
=-5.825
Rounded to two decimal places:
-5.83
So, the wait time decreases by about:
5.83 " minutes per hour "

The graph represents:
x(t)= " number of users watching a live video "
where:
t= " hours after 9:00 a.m. "
We are asked to interpret the concavity between:
t=3.2
and
t=5.7
On this interval, the graph is going downward, so the number of users is decreasing.
Also, the graph becomes steeper as it moves downward during this interval. That means the rate of decrease is becoming larger in magnitude.
In other words, the number of users is not just decreasing; it is decreasing more quickly as time passes.
So the correct interpretation is:
" The number of users is decreasing faster and faster. "
Therefore, the correct answer is:
# ( " C " )

The function is:
D(t)=48t+23
This is a linear function because it has the form:
D(t)=mt+b
where:
48
is the rate of change, and:
23
is the starting distance from the rest stop.
We need to find:
D(1.7)
That means substitute:
t=1.7
into the function.
D(1.7)=48(1.7)+23
First multiply:
48(1.7)=81.6
Now add 23:
D(1.7)=81.6+23
D(1.7)=104.6
So the vehicle is:
104.6 miles
from the rest stop after 1.7 hours.

This question asks us to identify a correct conclusion from the graph.
The vertical axis represents:
" number of daily homework problems "
The horizontal axis represents:
" school days since the beginning of the term "
From the graph, the lowest point occurs at the far right, around:
" day " 22
The corresponding number of homework problems is approximately:
18
So the minimum number of daily homework problems is 18, and it occurs at day 22.
Therefore, the correct answer is:
# ( " D " )

The function is:
f(x)=330× # 1.15 # ^x
Because xrepresents the number of years since 2005:
2006 # x=1
2011 # x=6
The average yearly rate of change from 2006 to 2011 is:
(f(6)-f(1))/(6-1)
First, find f(1):
f(1)=330× # 1.15 # ^1
f(1)=330×1.15
f(1)=379.50
Now find f(6):
f(6)=330× # 1.15 # ^6
f(6)#330×2.31306
f(6)#763.31
Now calculate the average rate of change:
(763.31-379.50)/(6-1)
=383.81/5
=76.762
Rounded to two decimal places:
76.76
So the average yearly rate of change of the artifact's value from 2006 to 2011 is approximately:
$76.76 " per year "
Therefore, the correct answer is:
# ( " A " )