1, the overdraft interest rate of ordinary credit cards is 0.05%, and the interest is equal to 100000 yuan times 30 days times 0.05% equals 1500 yuan.
2. The overdraft interest rate of the gold card is 0.04%, and the interest is equal to 100000 yuan multiplied by 30 days multiplied by 0.04%, which is equal to 1200 yuan.
3. The overdraft interest rate of Platinum Card is 0.03%, and the interest is equal to 65,438+000,000 yuan multiplied by 30 days multiplied by 0.03%, which is equal to 900 yuan.