4. Expected Benefits and Costs (20 points). The government is considering constructing a dam that will last for 5 years. If the dam is constructed, the annual benefit of the dam is $50 million. Assume that the benefits will start accruing at the end of the first year and accrue at the end of every year in which the dam operates thereafter. In order to construct the dam, there is an initial cost of 525 million that must be paid at the beginning of the first period. In addition, there is an annual maintenance cost that must be paid at the beginning of the year for all 5 years. This cost depends on the amount of rainfall. Every year can be a rainy year with probability (.7 and a dry year with probability 0.3. In a rainy year, the maintenance cost is $5 million, and in a dry year, the cost is $3 million. What are the net benefits of the dam? The real discount rate is 5% and all amounts are measured in real dollars