This is how exams are in Russian universities. You walk in. The table has a number of small paper cards on it face down with topics the course covered. You pick one at random, flip it over, and that is the question you need to answer. Since you do not know up front which you'll pick, you need to know all the material. Since you only need to answer one question, professor time is saved and exam throughput can be quite high.

Professors are also given quite a lot of flexibility in their grading. My mother had a fun story about a professor she had in college - a professor of a really hard math class who wanted to save on exam time. He announced "exam will be hard. Anyone willing to settle for a D, bring your report cards forward, I will mark them D and you can leave. No exam.". Some people came forward, got their Ds marked, and left. Once the door closed, he said "Anyone willing to accept a C, please come forward". Some did. After the door closed there, he announced to the remaining smiling students expecting easy As/Bs: "I'll see you all for the exam tomorrow 8 am".

No way this could happen in USA.