Let x represent the number of miles driven by both individuals.
Now, since COMPANY A will charge Teresa an initial constant fee of $58 and then an additional 40 cents (or $0.4) for every mile driven, we know that:
- if Teresa drives x miles, she will be charged:
![0.4\times x\text{ dollars}](https://tex.z-dn.net/?f=0.4%5Ctimes%20x%5Ctext%7B%20dollars%7D)
Therefore, in total, Teresa will be charged by company A the following:
![(58+0.4x)\text{dollars}](https://tex.z-dn.net/?f=%2858%2B0.4x%29%5Ctext%7Bdollars%7D)
Also, since COMPANY B will charge Teresa an initial constant fee of $40 and then an additional 69 cents (or $0.69) for every mile driven, we know that:
- if Teresa drives x miles, she will be charged:
![0.69\times x\text{ dollars}](https://tex.z-dn.net/?f=0.69%5Ctimes%20x%5Ctext%7B%20dollars%7D)
Therefore, in total, Teresa will be charged by company B the following:
![(40+0.69x)\text{dollars}](https://tex.z-dn.net/?f=%2840%2B0.69x%29%5Ctext%7Bdollars%7D)
Now, the milieage (x) for which both companies A will charge Teresa no more than company does is obtained by relating the expressions for their separate fees as follows:
![(58+0.4x)\text{dollars }\leq(40+0.69x)\text{dollars}](https://tex.z-dn.net/?f=%2858%2B0.4x%29%5Ctext%7Bdollars%20%7D%5Cleq%2840%2B0.69x%29%5Ctext%7Bdollars%7D)
Thus, we simply the above and solve for x, as follows:
![58+0.4x\leq40+0.69x](https://tex.z-dn.net/?f=58%2B0.4x%5Cleq40%2B0.69x)
Collect like terms:
![\begin{gathered} 0.4x-0.69x\leq40-58 \\ \Rightarrow-0.29x\leq-18 \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%200.4x-0.69x%5Cleq40-58%20%5C%5C%20%5CRightarrow-0.29x%5Cleq-18%20%5Cend%7Bgathered%7D)