Final answer:
The aggregate marginal damage for the public bad created by the pollution from a cheese factory is 8p, which is the sum of the marginal damages to workers (2p) and retirees (6p).
Step-by-step explanation:
The student has asked to find the aggregate marginal damage for the public bad created by a polluting cheese factory. To calculate this, we combine the marginal damage to workers and retirees. The marginal damage to workers is 2p and for retirees, it is 6p. Therefore, the aggregate marginal damage of pollution for both workers and retirees is 2p + 6p = 8p. This represents the extra cost on society for every additional unit of pollution emitted by the cheese factory. Understanding the aggregate marginal damage is crucial for policymakers to address the negative externality and reach a social optimum where market activities do not harm societal welfare.