Adley is a stingy donor. She originally donated $164 to Forest High School for its libray, but she cant stand a certain book series. Every time she sees a child reading a book from this series she will take back $9 from her donation. The following sequence shows how her donation decreases for each student she sees reading this book series: 164, 155, 146, 137, 128, 119, ... Which representations model this problem situation?