I am a number less than 40 one of my factor is 7 the sum of my digits is 8

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