Answer:
460 ft^2 of carpet will be replaced
Explanation:
You need to find the area of the room and then take away the area of the six bookcases
Area of the room
20*20=400ft^2
35-20=15ft
(15*20)/2=150ft^2
400+150=550ft^2 total room area
Area of bookcases
2.5*6*6=90ft^2 total bookcase area
room area - bookcase area = carpet area
550-90=460ft^2