Hi!
Let's find how many inches the walk needs to be.
6 * 12 = 72
24 * 12 = 288
72 inches wide, and 288 inches long.
Now find the area of the walk, and the brick.
Walk: 72 x 288 = 20736
Brick: 4 x 8 = 32
Now divide.
20736/32 = 648
The answer is 648 bricks.
Hope this helps! :)
-Peredhel