Final answer:
To calculate the interest charged on the credit card, subtract the amount paid off from the new cost of the iPhone 11 and multiply it by the interest rate and time. The interest charged is $45. The new total bill will be $545.
Step-by-step explanation:
To calculate the amount of interest charged on the credit card, we need to find the difference between the new cost of the iPhone 11 ($700) and the amount you paid off ($200). This difference will be the initial principal amount on which interest is charged.
Interest is calculated using the formula: interest = principal x rate x time. In this case, the principal is $500 (the remaining amount owed), the rate is 0.09 (9% as a decimal), and the time is 1 year since the interest is calculated annually for credit cards.
Using this information, we can calculate the interest charged: interest = $500 x 0.09 x 1 = $45.
To find the new total bill, we add the interest charged to the remaining amount owed: new total bill = $500 + $45 = $545.