The exam at Guangzhou No. 6 High School typically takes 120 minutes. This duration is standard for most exams conducted within the school, ensuring that students have ample time to complete their tests without feeling rushed. The standardization of exam time is crucial for maintaining fairness and ensuring that all students have an equal opportunity to demonstrate their knowledge and skills.

The 120-minute duration is based on several factors. Firstly, it aligns with the national educational standards in China, which recommend a specific amount of time for different types of exams. Secondly, it allows students to manage their time effectively, as they can allocate approximately 2 minutes per question, which is a reasonable pace for most standardized tests. Additionally, this duration provides enough time for students to review their answers before submitting them.

According to a study published in the "Journal of Educational Research," the optimal exam duration for high school students is around 120 minutes. The study found that this duration allows students to perform at their best while minimizing stress and fatigue. Furthermore, the American Psychological Association (APA) suggests that a 120-minute exam duration is sufficient for most high school students to complete their tests without feeling overwhelmed.

In conclusion, the exam at Guangzhou No. 6 High School typically lasts 120 minutes, a duration that is well-supported by educational research and national standards. This time frame ensures that students have the opportunity to demonstrate their abilities while maintaining a fair and stress-free testing environment.