I found this answer on another Brainly question so hope this helps.
Answer: 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