Two manufacturers, denoted 1 and 2, are competing for 100 identical customers. Each manufacturer chooses both the price and quality of its product where each variable can take any nonnegative real number. Let pi and xi denote respectively, the price and quality of manufacturer i's products. The cost to manufacturer I of producing for one customer is 10 +5 xi. Note in this expression that the cost is higher when the quality is higher. If manufacturer i sells to qi customers, then its total cost is qi(10 + 5x). Each customer buys from the manufacturer who offers the greatest value, where the value of buying from manufacturer i is 1000 + xi - pi; higher quality and lower price mean more value. A manufacturer's payoff is its profit, which equals qi(pi - 10 - 5 xi). If one manufacturer offers higher, then all 100 customers buy from it. If both manufacturers offer the same value, then 50 customers buy from each manufacturer. Find all symmetric Nash equilibria.