A students cost for last semester at her community college was 2100.she spent 315 of that on books. what is the percent of last semesters college costs was spent on books

Miriam bought a bushel of apples from the apple orchard to bake apple pies for a bake sale. she started with 126 apples. after the first day of baking, she had 108 apples left. after the second day, she had 90 apples. after the third day, she had 72 apples left. if she continues this pattern, how many apples will she have left after 7 days of baking? apples