Q3: Taking "Everyday Upward Education Gold" as an example, you purchased it when your child was just born, paying 50,000 annually for 3 years. When your child reaches 18-21 years old, the insurance company will give you 30,000 annually. At the age of 22, if you wish to terminate the policy, you can also receive a lump sum of 190,000. a. Assuming the interest rate is 3%, is this product worthy? b. If we don't know the interest rate, but we want to determine the lowest interest rate at which this product would be considered "fair". Just list the equation