For this problem we can create the following functions for the total cost for ech company like this:
[tex]Ca=90+50.4x[/tex][tex]Cb=30+50.60x[/tex]Where x represent the number of miles and Ca, Cb the cost for Company A and B respectively. For this case we can set up equal both costs and we got:
[tex]90+50.4x=30+50.60x[/tex]And if we solve for x we got:
[tex]90-30=(50.60-50.40)x[/tex][tex]60=0.2x[/tex]And solving for x we got:
[tex]x=\frac{60}{0.2}=300[/tex]And for this case we can conclude that x=300 miles in order to have the same rental costs for both companies
