Center A = $300 for a year (unlimited)
Center B = $35 + $15 a week + $5 per class.
12 months in a year, $15 * 12 = $180.
52 weeks in a year, $5 * 52 = $260.
Center B = $35 + $180 + $260 = $475.
$300 < $475, therefore A is less expensive to use for a year.