A ski resort has always relied on natural snow, which could come in any one of four levels: heavy, medium, light, or none, with probabilities 0.1, 0.4, 0.3, and 0.2 respectively. They are now, in July, considering the installation of an artificial snow-making system before the upcoming season. If installed, the annual amortized cost would be $40,000. The operating costs of the snow system would be $0 if the natural snow were heavy, $50,000 if medium, $80,000 if light, and $110,000 if there were no natural snow. With an artificial snow system, or with heavy natural snow, they would obtain revenue of $200,000. With no artificial snow, the revenue would be only $130,000 with medium snow, $70,000 with little snow, and $0 if there were no snow. Operating costs other than snow-making would be $45,000 per year (whether artificial or natural snow). Choosing, before the season begins, to close the operation completely for the upcoming season, would allow them to rent the land with a rental income of $20,000.

(a) Solve this problem using a decision tree. (b) Determine the EVPI by first finding the EV with PI.