Question

Julia spent $58 on a book. the cost of the book was $20 less than twice what she spent on a backpack. how much did the backpack cost?

Answer 1

58 + 20 = 78
78/2 = 39
backpack = $39

Answer 2

Book: 2(backpack) - $20 = $58
           2(backpack)         = $78
                backpack        = $39