CFR lvl 1 Practice Question vs. Exam

Hi guys,

I have been doing the practice questions on the official CFA study website and been getting an accuracy of 80 - 90% depending on the specific topic.

I wonder how comparable is the practice question to the actual exam. Will the real exam be harder or easier than the practice question? On average, what percentage of accuracy for practice questions would be needed to pass the exam? (assuming doing the practice questions without any notes)

Does anyone have any idea?