Sam is carpeting her living room and she needs to know how much carpet to buy. if the room is 8.5 feet long and 7.5 feet wide, how much carpet should she buy?

Assuming the room is a rectangle...
The area of a rectangle = its length × its width.
The amount of carpet we need to cover our rectangular room = 8.5 ft × 7.5 ft
Use decimal long multiplication or otherwise to get 63.75 ft².

Area of the room = (8.5ft) x (7.5 ft) = 63.75 square feet

But carpet is sold by the square yard.
1 square yard = 9 square feet

(63.75 square feet) x (1 square yard / 9 square feet) = (7 and 1/12) square yards.

If she tries to do the job with 7 square yards, then there'll be a little bare patch
somewhere in the living room.  Maybe she can hide it under the couch.

If she wants to cover every last square inch of floor in the room, then she'll
probably have to buy 8 square yards.  The carpet store won't want to cut
1/12 of a square yard for her.

So after the job is done, she'll have a nice piece of carpeting left over, with
11/12 of a square yard of area.  Maybe she could use it as a nice matching
cover for the coffee table in the living room, or else let the dog sleep on it etc.

The correct answer is -20y