Question 7I need the formula used and steps for solving Thanks

Q6. (5 points) The world is not perfect, and we can never know the future with real certainty. Why, then, should we use the expected value of perfect information (EVPI)? Q7. (15 points) Suppose that a Zoom cell phone customer has a choice of four monthly leasing plans: Plan I: $20 per month and $.40 per minute Plan II: $30 per month with 20 free minutes and $.30 per minute for additional minutes Plan III: $40 per month with 30 free minutes and $.20 per minute for additional minutes Plan IV: $60 per month with 100 free minutes and $.10 per minute for additional minutes Suppose also that the customer estimates that the amount of time he/she will talk on the cell phone each month can be approximated by the following distribution: Time Probability 10 minutes .20 30 minutes .20 60 minutes .30 100 minutes .20 150 minutes .10 Required: Determine which plan the customer should choose if the objective is to minimize the expected monthly cost