D.between 20 and 25 minutes
Explanation
Step 1
when you have 2 points of a lines, you can find the rate of change, using:
[tex]\begin{gathered} \text{rate of change= slope=}\frac{y_2-y_1}{x_2-x_1} \\ \text{where } \\ P1(x_1,y_1) \\ P2(x_2,y_2) \end{gathered}[/tex]
then
a) between 0 and 5 minutes
Let
P1(0,0)
P2(5,40)
apply the formula
[tex]rate_1=\frac{y_2-y_1}{x_2-x_1}=\frac{40-0}{5-0}=\frac{40}{5}=8[/tex]
b)between 5 and 10 minutes
Let
P1(5,40)
P2(10,50)
apply
[tex]rate_{2_{}}=\frac{y_2-y_1}{x_2-x_1}=\frac{50-40}{10-5}=\frac{10}{5}=2\text{ }[/tex]
c)between 10 and 20 minutes
Let
P1(10,50)
P2(20,50)
apply
[tex]\begin{gathered} rate_{3_{}}=\frac{50-50}{20-10}=\frac{0}{10}=0 \\ \end{gathered}[/tex]
d)between 20 and 25 minutes
Let
P1(20,50)
P2(25,40)
apply
[tex]\begin{gathered} rate_{4_{}}=\frac{y_2-y_1}{x_2-x_1}=\frac{40-50}{25-20}=\frac{-10}{5}=-2\Rightarrow negative \\ \end{gathered}[/tex]
so, the answer is D.between 20 and 25 minutes
