At a used book sale, Miss Chen bought a box of 20 assorted books for $40. What was the cost per book?

Answer 1

To find the cost per book, we need to divide the total cost by the number of books.

Total cost: $40

Number of books: 20

Cost per book = Total cost / Number of books
Cost per book = $40 / 20
Cost per book = $2

Therefore, the cost per book is $2. Answer: \boxed{2}.