3. There are 2 players. Each has an endowment of 10 dollars and chooses how many dollars to contribute to a public pool. Call x1 and x2 the contributions of player 1 and player 2, respectively. If X1+ X2 2 5, then players 1 and 2 receive a payoff of 10 - X1 + 1 and 10-X2 + 1, respectively. Otherwise they receive a payoff of 10 - x1 and 10 -x2, respectively. a) Find a Nash equilibrium of this game. b) Now suppose that if x1 + X2 2 5, players 1 and 2 receive a payoff of 10 - x1 +10 and 10 - x2 + 10, respectively. Find a Nash equilibrium of this game