Final answer:
Maintaining the current price is optimal for a parking lot with unitary price elasticity of demand and zero marginal cost when the lot is at full capacity, as these conditions result in maximized total revenue.
Step-by-step explanation:
Since the elasticity of demand for your parking lot spaces is -1 (unitary elasticity), and the lot is at capacity, maintaining the current price is the optimal pricing strategy. With unitary elasticity, the percentage change in the quantity demanded is equal to the percentage change in price, which means that your total revenue will stay the same whether you choose to slightly increase or decrease the price.
However, since the marginal cost (MC) is zero and the lot is full by 9 AM, you are already maximizing total revenue with the current pricing, according to the principles outlined in the reference information provided.
Following the concept of price elasticity of demand, if the elasticity was greater than 1 (elastic), a price decrease would lead to a more significant increase in quantity demanded, increasing total revenue. Conversely, if elasticity was less than 1 (inelastic), an increase in price would lead to a smaller percentage decrease in quantity demanded, resulting in increased total revenue.
Nonetheless, in the case of unitary elasticity and your parking lot being at full capacity, no price change is necessary as it won't impact the total revenue generated.