Answer:
a=$50 One time administration fee
Step-by-step explanation:
This is a function. Let's model it. Knowing that the Cost of Parking permit is made up of One time administration fee for all, and a monthly payment for everyone. What's changing here is the amount of Parking Time. So Let's model and solve this Linear System.
C(t)= Cost of Parking Permit. (t= time is given in months)
a= One time administration fee
b = monthly payment
First Case: A permit purchased for 12 months costs $660.
660=12a +b
Second case: A permit purchased for 15 months costs $810
810=15a+b
660=12a+b * -5 <em>Addition Method</em>
810=15a+b * 4
-3300=-60a-5b
3240= 60a+4b
--------------------------
-60=-b
b=60 monthly fee
Plug in the first equation to find out a.
660 =12a +60
660-60=12a
600=12a
a=$50 One time administration fee
Testing it
$660= 12(50)+60 as 810=15(50)+60 .