Patricia and John both used their credit cards to purchase $225.00 worth of gas and groceries for the month of July. Patricia paid off her credit card transactions on the same day that she made them, while John did not. They both received their credit card statements at the same time. Patricia's balance was zero, and she had only paid $225.00 to the credit card company. However, John had a finance charge of $3.82 added to his balance of $225.00. Explain why John had a finance charge and Patricia did not.