Answer: $13.25
Step-by-step explanation:
From the question, we are informed that an oral auction has bidders willing to pay $4, $6, $9, $12, $13, and $15 for an item.
Based on the above scenario, the winning bidder will pay a little more than $13 or $13.25. This is because the bidder with the highest pay is willing to pay $15 but since the next person is willing to pay $13, that means the next bidder will price it at an amount that is a little bit above $13 which is $13.25.