Consider an economy with two individuals. Individual 1 has (inverse) demand curve for a public good given by P1 = 60 - 2Q1, while Individual 2 has (inverse) demand curve for the public good given by P2 = 90 - 5Q2. The prices are measured in $ per unit. Suppose the marginal cost of producing the public good is $10 per unit. What is the efficient level of the public good?