Final answer:
At the point where marginal cost equals average variable cost, the average fixed cost is $0 since ATC equals AVC, and ATC is the sum of AVC and AFC.
Step-by-step explanation:
The student's question pertains to understanding the relationship between different types of costs in economics, specifically the average total cost (ATC), average variable cost (AVC), and average fixed cost (AFC). At the point where the marginal cost (MC) is equal to the AVC, the difference between the ATC and AVC will give us the AFC. Given that the ATC is $5 when MC equals AVC, and since at this point ATC and AVC are equal, the AVC is also $5. Therefore, the AFC at that point is $0, as ATC is the sum of AVC and AFC (ATC = AVC + AFC), meaning the AFC must be ATC - AVC, which is $5 - $5 = $0.