8. The Types of Goods

The benefit of an additional unit of a public good is:

If the benefit of a public good does not exceed its cost:

To find the benefit of an additional unit of a public good, we sum the individual demand curves:

Two roommates plan to spend their evening with a marathon of Saw horror movies. Because it is a marathon, they must start with the first movie in the series and continue in order. Their willingness to pay for the rental of each movie is as follows:The marginal benefit from renting the third movie is: 

Two roommates plan to spend their evening with a marathon of Saw horror movies. Because it is a marathon, they must start with the first movie in the series and continue in order. Their willingness to pay for the rental of each movie is as follows:If each movie rental costs $6, how many movies should they rent? 

Which of the following is not a possible solution to the tragedy of the commons?