Benny had 119 dollars to spend on 9 books. After buying them he had 11 dollars. How much did each bo

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Benny had 119 dollars to spend on 9 books. After buying them he had 11 dollars. How much did each book cost ?

Let each book cost "b". We have:
9b + 11 = 119

Using our equation calculator, we get b = 12.