Answer:
3 boxes
Explanation:
The walkway is 54 by 1.5 feet. This is an area of 54*1.5 = 81 square feet.
Each tile is 1.5 by 1.5 or has an area of 2.25 square feet.
Each box has 12 tiles or an area of 12*2.25 = 27 square feet.
The total area of 81 / 27 = 3. This means 3 boxes will cover 81 square feet.