The tiles do not have to be black, they just make it to be black.
Floor tiles do not kill cockroaches. You will need to use a pesticide.
52 tiles (with a bit left over !)
100 of them.
You would need 56 tiles to do the floor
108 carpet tiles
48 Get 52 to be safe.
28 You need to work out the area of the floor which is 5.5*5 = 27.5ft2 Your floor tiles are 1ft2 each so you need 27.5 of them. Generally you can't get half tiles so you'd need 28 and cut one in half.
If the floor tiles are measured in inches and the room is measured in feet then the tiles are 1sq feet and the room is 6x8 = 48 sq feet so you would need 48 tiles.