To figure this out you would need to create a rectangle with dimensions that give you an area of 7 ft.². The easiest example would be a rectangle that is one by seven. If the scale is 1:16, that means for every foot it is actually representing 16 feet. The actual length and width would be found by multiplying 1×16 and 7×16. The true dimensions then would be 16 x 112. Multiply this together to get a total area of 1792 ft.².
It would be: 20* 10 = 200 ft²
so, the carpet should have the area of about 200 ft²