Answer:
248 sq. ft
Explanation:
One method to solve this is:
Find the area of the pool by multiplying the width by the length, then add the width of the walkway and find the total area. And finally subtract the first product from the second to isolate the area of just the walkway.
So...
18 x 40 = 720
18 + 4 = 22 and 40 + 4 = 44
22 x 44 = 968
968 - 720 = 248