please explain and show work- please use correct grammar!! giving brainlest if explained

Answer: The answer is 14
Step-by-step explanation: So, for every 5 books she gets, she gets two free. Here is a chart
5 books bought=2 free books
10 books bough=4 free books
15 books bought=6 free books
20 books bought=8 free books
25 books bought=10 free books
30 books bought=12 free books
35 books bought=14 free books
Every five books bought equals two free books, so if she buys 35 she would get 14, so 49 books in all. hope this helps :)