Judy isn't sure whether a credit card using the average daily balance method, a credit card using the previous balance method, or a credit card using the adjusted balance method is right for her. Regardless of the method used, Judy's APR will be 26%. Her last 30-day billing cycle was typical for her, so she decided to calculate the amount of interest charged by each method to compare them. The opening balance of her last 30-day billing cycle was $930, and it remained that amount for the first 10 days of the billing cycle. She then made a purchase for $550, so her balance jumped to $1480, and it remained that amount for the next 10 days. Judy then made a payment of $790, so her balance for the last 10 days of the billing cycle was $690. Help Judy decide which method is best for her based on her last 30-day billing cycle. Part I: What is Judy's average balance for her billing cycle?

Part II: If Judy's credit card had used the average daily balance method, how much would she have been charged in interest for her last 30-day billing cycle?

Part III: If Judy's credit card had used the previous balance method, how much would she have been charged in interest for her last 30-day billing cycle?

Part IV: If Judy's credit card had used the adjusted balance method, how much would she have been charged in interest for her last 30-day billing cycle?