The Skubic family and the Shaw family went on a safari tour in which they drove their own vehicles through the park to view the animals. The cost of the tour was $5.25 per vehicle plus an additional amount for each person in the vehicle. The Skubic family had 7 people in their vehicle and paid $22.75. If the Shaw family had 3 people in their vehicle, how much did they pay?

$2.50
$7.50
$12.75
$17.25