Answer:
Explanation:
First, we write the rental cost with each company:
Company A
![Pa = 100 + 0.2*m](https://img.qammunity.org/2020/formulas/mathematics/middle-school/uryoo4ik9364eaxkreyq0gwnbvxhossk6y.png)
Company B
![Pb = 60 + 0.7*m](https://img.qammunity.org/2020/formulas/mathematics/middle-school/4e763b93ict5mj5cq7mzo0emhx1e0utwnl.png)
Where m: miles travelled
Now, we need to find "number of miles in a day at which the rental costs for Company A and Company B are the same". This means Pa = Pb. Then:
![100 + 0.2*m = 60 + 0.7*m](https://img.qammunity.org/2020/formulas/mathematics/middle-school/g48bq3oy31o3fws79qfmmdmye8b72bhuyu.png)
Solving the equation for m by taking 0.2m and 60 on both sides:
![100 + 0.2*m - 0.2*m - 60 = 60 + 0.7*m - 0.2*m - 60](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rsvg49xthomk115st2m3ha1xuvy2yrr4ri.png)
![40 = 0.5*m](https://img.qammunity.org/2020/formulas/mathematics/middle-school/a07vfmx2mxo152peh0580kfjtvstvfa433.png)
Finally, dividing 0.5 on both sides:
![m = 80](https://img.qammunity.org/2020/formulas/mathematics/middle-school/54wup5enies81fw3ibvi8ytt5hy8osxz8j.png)