I got that r, the regular price of the monthly fee is 62.
So first I started with the equation;
[tex]392.50 = 10( \frac{1}{2} r+ 8.25) [/tex]
then I divided both sides by 10 which then gave me;
[tex]39.25 = \frac{1}{2} r + 8.25[/tex]
after that, I subtracted 8.25 from both sides;
[tex]31 = \frac{1}{2} r[/tex]
then I multiplied by 2 to get R alone and that's how I got 62
