Dan had 249 dollars to spend on 7 books. After buying them he had 18 dollars. How much did each book cost?

First, lets subtract the amount he has after the transaction and the amount he had before the transaction.

249 - 18 = 231

Second, divide by the amount of books Dan bought.

231 / 7 = $33 per book.

Best of Luck!

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".