first we writte the information they are giving to us:
For company A:
initial fee = $90
rent per mile = $2
For combany B:
initial fee = $50
rent per mile = $3
Now for company A the equation that represent the charge in one mile will be: (where n is the number of miles)
[tex]\begin{gathered} A=90+2(n) \\ A=90+2(1) \\ A=90 \end{gathered}[/tex]And for company B:
[tex]\begin{gathered} B=50+3n \\ B=50+3(1) \\ B=53 \end{gathered}[/tex]Now to determine the number miles driven, that would make the cost of each company the same, we have to make A = B
[tex]\begin{gathered} A=B \\ 90+2n=50+3n \\ \end{gathered}[/tex]and finaly we can solve for n
[tex]\begin{gathered} 90-50=3n-2n \\ 40=n \end{gathered}[/tex]so if they drive for 40 miles the will pay the same