The equations are
[tex]\\ \tt\hookrightarrow y=0.50x+75[/tex]
[tex]\\ \tt\hookrightarrow y=0.55x+69.10[/tex]
Now
[tex]\\ \tt\hookrightarrow 0.55x+69.10=0.50x+75[/tex]
[tex]\\ \tt\hookrightarrow 0.55x-0.50x=75-69.1[/tex]
[tex]\\ \tt\hookrightarrow 0.05x=5.9[/tex]
[tex]\\ \tt\hookrightarrow x=5.9/0.05[/tex]
[tex]\\ \tt\hookrightarrow x=118mi[/tex]