Answer:
He needs to buy 7 boxes of carpet squares.
Explanation:
Mr. Cullen needs 91 carpet squares and he already has 49 carpet squares.
This means that he needs:
91 - 49 = 42 carpets squares
He needs 42 carpets squares.
The carpet squares are sold in boxes of 6.
Since Mr Cullen needs 42 carpet squares, the number of boxes he will need to buy can be gotten by dividing the number of carpet squares he needs (42) by the number of carpet squares in a box (6).
That is:
42 / 6 = 7 boxes
He needs to buy 7 boxes of carpet squares.