She does have enough paint.
all you need to do is multiply 11 1/2 and 8 1/2. You do not need to include the area of the door because it is inside the wall’s area already.
11 1/2 * 8 1/2 = 97.75 sq ft
97.75 sq feet is less than 100 sq feet, so Amelia will have enough paint left.