Final answer:
By calculating the price per book for both Miss Sang ($12.16/book) and Mr. Evans ($11.00/book), it is determined that Mr. Evans pays the lower price per book for purchasing books for the school library.
Step-by-step explanation:
To determine who pays the lower price per book between Miss Sang and Mr. Evans, we need to calculate the price per book for each of them. For Miss Sang, the price per book is calculated by dividing the total cost by the number of books: $669 divided by 55 books equals $12.16 per book. For Mr. Evans, the price per book is $737 divided by 67 books, which equals $11.00 per book. Comparing the two, we can see that Mr. Evans pays a lower price per book than Miss Sang.