Answer: $35.00
Step-by-step explanation:
The optimal quantity of a public good simply occurs when the demand which is the marginal benefit curve and the supply which is the marginal cost curve intersects
In this case, the marginal social benefit will be:
= Sanjay's marginal benefit + Anjali's marginal benefit
= $10 + $25 = $35.
Therefore, the answer to the question is $35.