Assuming that 12 x 12 is 12" x 12" (one square foot), then 30 one-square-foot tiles would cover 30 square feet.
80
6' x 9' (54 square feet) = 6 square yards of tiles needed.
If that is 2' x 4' it would cover 800 square feet. If it is 2" x 4" it would cover about 5.5 square feet.
just do 249 divided by 18
80 if the tiles are 12x12 - 12x12 is one square foot covering 80 you would need 80 tiles
Tiles that are two feet on a side cover 4 square feet. 378 of them cover 1512 square feet.
192 tiles
76.6 tiles
67 tiles.
190
Two tiles will suffice since they will cover 36 square feet.
start with 38 tiles.
Since a 12x12 tile is one square foot, then 38 12x12 tiles will cover 38 square feet.
500/1.78 = 281 tiles
157 18 by 18 tiles are needed to cover 352 square feet.
You will need at least 67 tiles. This will cover 150.75 square feet.
Each tile covers 4 square feet. You will need 24.75 tiles to cover the area.