According to the hypothetical conditions, if the credit card is overdue for one year, the interest will be 10 yuan.

Detailed instructions:

1. Assume that the annual interest rate of the credit card is x. The interest for one year overdue can be calculated as: 10 yuan = (x/100) * 10 yuan * 1 year.

2. Simplify the above equation: 10 = 0.1x the first year.

3. Solve the equation to get x = 100 yuan/year.

4. Therefore, assuming that the annual interest rate of a credit card is 100, that is, 100 of the principal should be repaid as interest every year, then the interest for one year overdue is 10 yuan.

Summary:

According to the hypothetical conditions, if the credit card is overdue for one year and the annual interest rate of the credit card is 100, then the interest for the overdue credit card for one year will be 10 yuan.

Extended information:

1. In actual circumstances, the overdue interest rate of a credit card is usually higher than the normal annual interest rate, and there may be additional charges such as penalty interest and late fees.

2. Different banks may have different regulations on credit card overdue interest rates. It is recommended to check the relevant policies of specific banks to obtain accurate information.

Please note that the above answers are based on assumptions and the actual situation may be different.