In the land of Nod, there are two ethnic groups: The Blueskins, whose native language is Bluish, and Greenskins, whose native language is Greenish. There are 600 Blueskins and 400 Greenskins. Anyone can learn other group's language for cost of $150. The value of having a common langage with another person is equal to $1 per person. A strategy includes a yes/no decision on whether to learn the other group's language.
a) Determine a Nash equilibrium in which some, but not all, Blueskins learn to speak Greenish and some, but not all, Greensins learn to speak Bluish. ("Find a Nash equilibrium" means: Determine exactly how many in each group learn to speak the other language.)
b) Is the Nash equilibrium in part a) Pareto optimal?
c) Are there any other Nash equilibria?