Is it better to study past questions or textbooks?

Use both, but not equally.

Past questions tell you how JAMB asks. They reveal patterns, timing and the traps in the options. They are the best use of your practice time.

Textbooks and the syllabus tell you what you do not know. If you only memorise past questions, a reworded question exposes the gap.

A practical split:

• 70% practice questions, always timed and always reviewed.
• 30% targeted reading on topics where your error log keeps showing weakness.

Do not "study" by reading a past-question PDF like a novel. Cover the answer, attempt it, then mark it. The learning happens in the correction.