Final answer:
The marginal cost of the drink in the value meal is the additional cost beyond the burger and fries bought separately, which is $0.50.
Step-by-step explanation:
The question is asking to determine the marginal cost of the drink in the value meal at a fast-food restaurant. To find this, you subtract the combined cost of the burger and fries when purchased separately from the cost of the value meal. A burger costs $4.00, and fries cost $1.50, which add up to $5.50. Since the value meal (including the burger, fries, and a drink) is priced at $6.00, the additional cost or marginal cost of the drink is $6.00 - $5.50, which is $0.50.