We can assign a function, for the value spent in each company as a function of the miles driven. For company A, we have no initial fee but a charge of 70 cents for every mile driven. We can write the function like this:
[tex]C_A(m)=0.7m[/tex]
For company B, we have an initial fee of $65 and an additional 60 cents for every mile driven. We can write the function like this:
[tex]C_B(m)=65+0.6m[/tex]
The problem wants us to know for what mileages will Company A charge more than Company B, in other words, when will C_A be bigger than C_B.
We need to solve the following inequality:
[tex]C_A(m)>C_B(m)\Rightarrow0.7m>65+0.6m[/tex][tex]\begin{gathered} 0.7m>65+0.6m \\ 0.7m-0.6m>65+0.6m-0.6m \\ 0.1m>65 \\ m>\frac{65}{0.1} \\ m>650 \end{gathered}[/tex]
With this, we have our answer. For any mileage bigger than 650, Company A will charge more.