Sarah had 207 dollars to spend on 9 books. After buying them she only have 18 dollars. How many books did she buy
Let's assume that Sarah bought x books.
We know that she had 207 dollars to spend on 9 books, so the cost of each book would be:
207/9 = 23 dollars per book
If she bought x books, then the total cost of those books would be:
23x dollars
We also know that after buying the books, she only had 18 dollars left. So we can set up an equation:
207 - 23x = 18
Solving for x, we get:
23x = 189
x = 8.217
Since Sarah cannot buy a fraction of a book, we can round down to the nearest whole number. Therefore, Sarah bought 8 books.