Answer:
$300 per unit; $100 per unit
Step-by-step explanation:
Given that,
costs $5,000 to produce 10 visits
Costs $6,000 to produce 20 visits
At a volume of 20,
Average Cost = Total cost ÷ Total Volume
 = $6,000 ÷ 20
 = $300 per unit
Marginal cost = Incremental Cost ÷ Incremental Units
 = ($6,000 - $5,000) ÷ (20 - 10) 
 = $100 per unit