There are 30 books in a bookcase. The books in the bookcase are all poetry, history, and art books. Ten of the books are art books. There are 6 fewer poetry books than history books. How many poetry books are in the bookcase?

How many books must you borrow to display all the books.

You fill the shelves of each bookcase in order, starting with the top shelf how many books are on each shelf of the last bookcase.

30 - 10 art books = 20

20 - 6 = 14

14/2 = 7 poetry books

7 + 6 = 13 history books

14

13

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To find the number of poetry books in the bookcase, let's break down the given information step by step.

First, we are given that there are 30 books in total. We can use this information to create an equation:

Poetry books + History books + Art books = Total books

Next, we are told that there are 10 art books, so we can replace "Art books" with 10 in our equation:

Poetry books + History books + 10 = 30

Now, we also know that there are 6 fewer poetry books than history books. So, we can express this relationship as:

Poetry books = History books - 6

We can substitute this expression for "Poetry books" in our previous equation:

History books - 6 + History books + 10 = 30

Combining like terms, we get:

2 * History books + 4 = 30

Subtracting 4 from both sides of the equation, we have:

2 * History books = 26

Dividing both sides by 2, we find:

History books = 26 / 2 = 13

Finally, substituting the value of "History books" back into the expression for "Poetry books":

Poetry books = 13 - 6 = 7

Therefore, there are 7 poetry books in the bookcase.