Answer:
[tex]D_{up}(t)=3t[/tex]
[tex]D_{down}(t)=8t[/tex]
[tex]D_{flat}(t)=5t[/tex]
Explanation:
To construct a linear model of their distance, in miles, as a function of time in hours, since we were given their traveling speed in miles per hour, simply multiply the traveling speed in mph by the time, t, in hours.
When traveling up a hill:
[tex]D_{up}(t)=3t[/tex]
When traveling down a hill:
[tex]D_{down}(t)=8t[/tex]
When traveling along a flat portion:
[tex]D_{flat}(t)=5t[/tex]