Question 1139728
<pre>

INTERSTATE           r+25     420/(r+25)      420

COUNTRY              r         135/r          135

Total                            9
</pre>

{{{420/(r+25)+135/r=9}}}

--


{{{140/(r+25)+45/r=3}}}

.

.
{{{3r^2-110r-1125=0}}}


discriminant is  {{{160^2}}};


{{{r=(110+160)/6}}}

{{{r=270/6}}}

{{{highlight(r=45)}}}