1,000 tiles.
Tiles that are two feet on a side cover 4 square feet. 378 of them cover 1512 square feet.
192 tiles
A 19.75 x 19.75 inch tile covers 390.0625 square inches, or 2.70877 square feet (divide by 144, which is 122, since we're working in square quantities). 1000 / 2.70877 = 369.171 tiles to cover the given area. (Were you to purchase tiles to actually do this, you'd haver to buy at least 370 tiles, since you can't buy 0.171 tiles.)
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
It will require a minimum of 1,462 tiles. That number will cover about 1,850.34 square feet.
If the 6x12 tiles are in inches, it will take two of them to cover a square foot. You will need 210 of them.
You will need at least 67 tiles. This will cover 150.75 square feet.
500/1.78 = 281 tiles