Solving problems from the previous Olympiad papers is an excellent way to prepare for any Olympiad. The purpose of this post is to share the recent papers of USA Astronomy and Astrophysics Olympiad and Indian Astronomy Olympiad in order to help you with the upcoming national round of Bangladesh Astronomy Olympiad. Do try to come out with your own solution first, and then, review their solution.
A personal note: In the chronicles of Bangladesh Astronomy Olympiad, students have observed the tendency to repeat the problems of Indian National Astronomy Olympiad in Bangladesh's Astronomy Olympiad, which undoubtedly shows the ineptitude of the problem setter. However, I'm hoping that there won't be any repetition of Indian Astronomy Olympiad's problems and participants will get a fair chance. Best wishes for all of you!