Josh paid for three books with two $20 bill. He received $1in change each book was the same price. How much did each book cost?

The total payment is:

P = 2 * ($ 20) = $ 40

The change is:

C = 1 $

The total cost is then:

CT = P-C = 40 $ - 1 $ = 39 $

"each book was the same price":

Book price = ($ 39/3) = $ 13

Answer:

each book cost:

Book price = 13 $