u/Ok_Yogurtcloset_300

So I just got my first kindle(12th gen paperwhite) and I've heard that the batteries last a really long time but just after setting up my kindle it's draining faster than expected. In about 15-20 mins it went from 52 to 48 percent. Is this normal??

I'm an 11th grade student(CBSE). I know it's late but I have to start prepping for the AMC12 and not to mention this is my first pre olympiad so I have no idea what to expect or what to study. I'm confused on what to study like do I do any past papers, books, courses, etc.