160 of them.
To determine how many 18x18 inch tiles are needed for a 42 square foot bathroom, first convert the tile size to square feet. An 18x18 inch tile is 1.5 feet by 1.5 feet, which equals 2.25 square feet per tile. Then, divide the total bathroom area (42 square feet) by the area of one tile (2.25 square feet): 42 ÷ 2.25 = 18.67. Since you can't use a fraction of a tile, you would need 19 tiles to cover the bathroom.
144
18..
A 19' x 15' room is 285 square feet or 26.477 square meters.
18 x 18 inch square is equal to 3/2 x 3/2 foot square = 9/4 square foot. To cover 154 foot square (you don't mean 154 square feet) is (154 x 154) / (9/4) = (154 x 154 x 4) / 9 = 10540.44, so you will need 10541 tiles
1
144
To determine how many 18x18 inch tiles are needed for a 42 square foot bathroom, first convert the tile size to square feet. An 18x18 inch tile is 1.5 feet by 1.5 feet, which equals 2.25 square feet per tile. Then, divide the total bathroom area (42 square feet) by the area of one tile (2.25 square feet): 42 ÷ 2.25 = 18.67. Since you can't use a fraction of a tile, you would need 19 tiles to cover the bathroom.
144
18..
6
A 19' x 15' room is 285 square feet or 26.477 square meters.
18 x 18 inch square is equal to 3/2 x 3/2 foot square = 9/4 square foot. To cover 154 foot square (you don't mean 154 square feet) is (154 x 154) / (9/4) = (154 x 154 x 4) / 9 = 10540.44, so you will need 10541 tiles
240 square tiles are needed
One, if it is big enough.
To cover an area of 1 square foot with 1/2 inch of water, you would need 0.623 gallons of water.
A square foot will cover a square foot, regardless of the depth of the material the cover is made of.