save user progress and show them the progress by percentage [on hold]

I am new to Android development and currently developing an android app for my final project. The app will let user answer quiz questions (like trivia) and the quiz will have 4 chapters. If the user not yet finish answering chapter 1, chapter 2 and others will be locked.

My question is, how do I save user's progress in which chapter they have answered so far and how to show them the progress by percentage. For example if they answered 2 chapters their progress would be 50%.