Fred had 156 dollars to spend on 9 books. After buying them he had 12 dollars. How much did each boo

Fred had 156 dollars to spend on 9 books. After buying them he had 12 dollars. How much did each book cost?

Subtract the 12 dollars left over from the $156 starting amount:
$156 - $12 = $144

Now divide $144 / 9 books to get the cost per book:
$144/9 = $16 per book