The cost of a parking permit consists of a one-time administration fee plus a monthly fee. A permit purchased for 12 months costs $⁢660. A permit purchased for 15 months costs $⁢810. What is the administration fee?

The extra 3 months increase the cost by $810 − $660 = $150, so the monthly fee is $150 ÷ 3 = $50. Subtract the 12 months of fees from the 12-month total: $660 − (12 × $50) = $60. The administration fee is 60 dollars, choice D.

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