Let x be the number of books that need to be sold, then for the cost of the production and the profit to be the same we can set the following equation:
![30456+10x=21.75x\text{.}](https://img.qammunity.org/2023/formulas/mathematics/high-school/w1zjvg493bnirqrnd5g5uwp54wa3i7xsft.png)
Subtracting 10x from both sides of the equation we get:
![30456=21.75x-10x,](https://img.qammunity.org/2023/formulas/mathematics/high-school/jw8klaow8z3rdxqkuwvyocyumjazpsb4vh.png)
adding like terms we get:
![30456=11.75x\text{.}](https://img.qammunity.org/2023/formulas/mathematics/high-school/c373u9hce61qdpf90rqcpuj8nirnwuqw46.png)
Dividing by 11.75 we get:
![x=2592.](https://img.qammunity.org/2023/formulas/mathematics/high-school/i34ck3z18yegqcx9k6dljxogfhkh1g24wd.png)
Then the producer must sell 2592 books.
Answer: 2592.