3. Create the logic for a program that accepts input values for the projected cost of a vacation and the number of months until vacation. Pass both values to a method that displays the amount you must save per month to achieve your goal.

To create the logic for the program, you'll need to:

1. Define the variables: You'll need two variables to store the input values - one for the projected cost of the vacation and another for the number of months until the vacation.

2. Get input values: You can use the appropriate method to accept input values from the user for both the projected cost of the vacation and the number of months until the vacation.

3. Define a method: Create a method that takes the projected cost and the number of months as parameters.

4. Calculate the amount to save per month: Inside the method, divide the projected cost by the number of months to determine the amount to save per month. Assign this value to a variable.

5. Display the result: Finally, display the calculated amount to save per month to achieve the vacation goal.

Here's an example of the logic in Python:

```python
def calculate_savings(projected_cost, number_of_months):
amount_to_save_per_month = projected_cost / number_of_months
return amount_to_save_per_month

projected_cost = float(input("Enter the projected cost of the vacation: "))
number_of_months = int(input("Enter the number of months until vacation: "))

savings_per_month = calculate_savings(projected_cost, number_of_months)
print("To achieve your vacation goal, you must save $", savings_per_month, " per month.")
```

By following this logic, you can create a program that accepts input values for the projected cost of a vacation and the number of months until the vacation, and then displays the amount that needs to be saved per month to achieve the goal.