Jillian spent $31 to park for 6 hours. The parking garage charges a base rate of $3 for the first 2 hours, and then an hourly rate for each additional hour. How much does each additional hour of parking cost?

8.50
5.17
4.67
7.00

The additional cost for each hour of parking can be calculated by subtracting the base rate from the total amount paid and then dividing by the number of additional hours of parking.

Total cost - Base rate = Additional cost for additional hours
$31 - $3 = $28 (Total cost for additional hours)
$28 / 4 (Number of additional hours) = $7 (Cost per additional hour)

Therefore, each additional hour of parking costs $7.