human
Elly is organizing her books on the new bookcases her parents bought her. Each of the middle 2 shelves can hold 10 books. The bottom shelf can hold twice as many books as a middle shelf. The top shelf can hold 5 fewer books than the bottom shelf. If she has 110 books, how many bookcases does she need to hold all of them?
assistant
How many books can the bottom shelf hold? ** The bottom shelf can hold 2 * 10 = <<2*10=20>>20 books.
How many books can the middle shelves hold? ** The 2 middle shelves can hold a total of 2 * 10 = <<2*10=20>>20 books.
How many books can the top shelf hold? ** The top shelf can hold 20 – 5 = <<20-5=15>>15 books.
How many books can each bookcase hold? ** Each bookcase can hold a total of 20 books + 20 books + 15 books = <<20+20+15=55>>55 books.
How many bookcases does she need to hold all of her books? ** To hold all of her books, she needs 110 / 55 = <<110/55=2>>2 bookcases.
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