Final answer:
The duration of a national examination is not explicitly stated, but the nature of the question implies it's likely a few hours, enough to test various skills including reading, writing, and speaking. Time management is crucial for students to complete the exam within the specified time frame.
Step-by-step explanation:
The time allocated to complete a national examination can vary depending on the subject and the rules established by the examination body. However, if we refer to the table provided, specifically in Solution 2.20, it indicates that 25% of students finished the exam in 35 minutes or less, which suggests that the exam was designed to be completed in a period around that time, though not all students may use the full time allotted. Furthermore, the reference to studying like the quiz was going to be proctored in a classroom and the importance of time management imply that a national examination has a fixed limited timeframe to complete. Since there is a mention of doing something 'in two hours' and an interview process that includes reading, writing, and speaking English, it suggests the exams in question might span several hours and incorporate diverse evaluation methods.
It is essential for students to be aware of the time limit for their specific examination and to practice time management skills to ensure they can complete all questions within the allotted time.