Given:
The distance (in kilometers) Dora hiked is modeled as a function of time.
We need to determine the average rate of change in distance hiked, measured in kilometers per hour, between 8:30 am to 1:30 pm.
Average rate of change:
Let us write the time and the distance hiked in coordinates for the time 8:30 am and 1:30 pm.
Thus, the coordinates are (8.30, 4) and (1,12)
The average rate of change can be determined using the formula,
![m=(y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/e9lgdayfzr27dyurvzbw9lffpiv7535tiv.png)
Substituting the points (8.30, 4) and (1.30,12), we get;
![m=(12-4)/(1.30-8.30)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/anohvbrbs9wdnnrjpkmnie1og1rl2dohf1.png)
![m=(8)/(-7)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/pwegbkgvfoce5ftu8s0xvd6xg5ults4121.png)
![m=-1.14](https://img.qammunity.org/2021/formulas/mathematics/middle-school/zz94ywpnyqx5wo2kqvha7ng7yw9z3yyi4c.png)
Rounding off to the nearest whole number, we get;
![m=-1](https://img.qammunity.org/2021/formulas/mathematics/high-school/1fx57sayebku9st01vjy1wvoslji0iuyjs.png)
Therefore, the average rate of change is -1.