63 ft
the area of her floor is 144 (12 × 12)
the area of the rug is 81 (9 × 9)
144 - 81 = 63
The correct and best answer would be letter B. To find the percent of a discount, you have to find or solve for the percent of increase from the new price to the original price. This is because you usually have the new price being given to you so you compare it with the old price to know the percent discount.
