Answer:
Cost of visit = 50 + 100n
Explanation:
$50 is the set price of the visit.
$100 is the cost per cavity.
N is the number of cavities.
Since we don't know the number of cavities, 'n' will fill that spot.
100 x n will be the total cavity cost.
Cavity cost + set price of visit will equal the total cost of the visit.