Tiles that are two feet on a side cover 4 square feet. 378 of them cover 1512 square feet.
192 tiles
Since a 12x12 tile is one square foot, then 38 12x12 tiles will cover 38 square feet.
Two tiles will suffice since they will cover 36 square feet.
Each tile covers 4 square feet. You will need 24.75 tiles to cover the area.
76.6 tiles
67 tiles.
190
If the 6x12 tiles are in inches, it will take two of them to cover a square foot. You will need 210 of them.
It will require a minimum of 1,462 tiles. That number will cover about 1,850.34 square feet.
You will need at least 67 tiles. This will cover 150.75 square feet.
500/1.78 = 281 tiles