Question 1139944
The long wall is 48 x 18 or 864 ft^2.  There are two, so that is 1728 ft^2

The short wall is 36 x 18 or 648 ft^2.  There are two, so that is 1296 ft^2
The total is 3024 ft^2, so 8 cans would be needed to completely cover, 3024/400 rounded upward.