A village has six residents, each of whom has accumulated savings of $100.

A village has six residents, each of whom has accumulated savings of $100. Each villager can use this money either to buy a government bond that pays 15 percent interest per year or to buy a year-old llama, send it onto the commons to graze, and sell it after 1 year. The price the villager gets for the 2-year-old llama depends on the quality of the fleece it grows while grazing on the commons. That in turn depends on the animal’s access to grazing, which depends on the number of llamas sent to the commons, as shown in the following table: