Production cost: y
Number of books: x
First method:
the one-time fixed costs will total $18,813 and the variable costs will be $25 per book

Second method:
the one-time fixed costs will total \$64.408 , and the variable costs will be 11.25 per book

For how many books produced will the costs from the two methods be the same?
Equal the funtions (equal the production cost of both methods) and solve to find x (number of books):

Then, the corst from the two methods is the same with 3316 books produced