The audio files for the entrance exam are about 4 minutes long. That's not long at all for transcription. The test is designed to make sure that candidates can understand and apply the style guide, which they are provided prior to taking the exam. You can take as much time as you need to study it before attempting the exam, and you can refer to it while taking the exam. If you don't pass the exam the first time, you can take it again. I suggest re-reading the style guide before taking the retry.