Your question is Design Borrow Book App. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Design an application which can enable user to borrow book.
Explain how users discover eligible books, how availability and borrowing rules are enforced, and where machine learning improves search or recommendations. Cover the end-to-end architecture, scale assumptions, serving path, evaluation, and key failure modes.