In practice you will use more tiles than the equivalent area of the room. A 15 foot strip of tiles will require 15 times 12/13 = 13.846 tiles to cover it. This will have to be rounded to 14 tiles. That means that the 15 foot by 15 foot room will require 14 times 14 tiles = 196 tiles to cover it. And that's if you don't drop and break any or mess up one or more cuts.
144
6.75 Tiles
-3.5
95 of them. Get 105 for breakage.
A 13 x 13 tile is 1.74 sq ft. 144/1.74 = 123 tiles
35
144
144 assuming no waste.
41
Scrabble tiles are 0.75 inch × 0.75 inch square. Therefore, one square foot of Scrabble tiles will include 256 tiles in a square of 16 X 16 tiles.
Floor area = 12 ft x 18 ft = 216 square feet. There are 4 six-inch square tiles needed for each square foot, so 864 tiles are needed.
6.75 Tiles
-3.5
236 18-inch tiles.
95 of them. Get 105 for breakage.
nine
A 13 x 13 tile is 1.74 sq ft. 144/1.74 = 123 tiles