A small manufacturer uses an industrial boiler in its production process. A new boiler can be purchased for $10000. As the boiler gets older, its maintenance expenses increase while its resale value declines. Since the boiler will be exposed to heavy use, the probability of a breakdown increases every year. Assume that when a boiler breaks down, it can be used through the end of the year, after which it must be replaced with a new one. Broken down boilers have no resale value. Use a decision tree to determine which year of operation should the boiler be replaced?