113
You would have 79 tiles.
49 tiles
That would depend on the size of the tiles.
You would need 173 tiles (you would have fractions of tiles left over)
1500 tiles
81 tiles squared because if it's a square then it would be 9x9 which is 81
None. No number of gray tiles will make a white tile.
123 tiles
You would need 358 tiles.
Assuming you mean the tiles are 16 inches square - you would need 169 tiles.
It depends on how big your tiles are