Answer: The formula for the interest charged on a credit card debt is:
Interest = (Principal * Annual Interest Rate) / 12
We know that the interest charged last month is $55, and the principal (the credit card debt) is $6000, so we can substitute these values into the formula and solve for the annual interest rate:
55 = (6000 * r) / 12
To find the annual interest rate, we will solve for r.
r = (55 * 12) / 6000
r = 0.09 which is a 9% annual interest rate.
So, the annual interest rate on the credit card is 9%.
Explanation: