I passed my PSM I exam today with a 90%, thank you to all members who have posted advice on how to study and pass this exam. I only had to take it once.
The real exam has some questions from the open assessments but most of the questions are geared towards how to apply your Scrum knowledge in real-world settings. You'll have to really understand the concepts and be able to interpret them in a work place setting.
What I did:
1. Read, re-read, and re-read The Scrum Guide
2. Read Scrum Forum posts of other people's experiences