Suppose carpet for a 10ft by 8 ft room costs $300. Find the cost to carpet a room
20 ft by 16 ft.
The cost to carpet the room is $
10 x 8 =80 square feet - area of the first room
$300 / 80 =$3.75 - cost of carpet per square foot.
20 x 16 =320 square feet - the area of the second room
320 x $3.75 =$1,200 cost of carpeting the second room.
+394 
