The area of the room cannot be 64 ft since that is a linear measure, not the measure of an area.
20" = 2.78 square feet. Now divide the area of the tiles into the area of the room. 140/2.78 = 51 tiles
Area of room = 5' * 6' = 30 square feet. Assuming the tiles are 12 * 12 square inches (not sq cm) then the area of each tile is 1 square foot and so 30 tiles are needed.
16 square tiles
First we need to calculate the square footage of the room. 15*20 = 300 square feet Now we need to know how many square feet each tile covers. 20" = 1.667~ square feet 1.6672 = 2.78 square feet. Now we divide the area of the tiles into the area of the room. 300/2.78 = 108 tiles. This gives the exact number of tiles you need mathematically. Realistically you need to account for cutting and breaking. It's safe to round that up to 120 tiles.
13 feet by 12 feet is the same as 156 inches by 144 inches. Multiply 156 by 144 to find that the room's area is 22464 square inches. Next, find the area of each tile by multiplying 13 by 13 to get 169 square inches. We need to find how many 169 square inch tiles can fit in a 22464 square inch room, so divide 22464 by 169 and get 132.923077. Round that up to the nearest whole number and get:133 tiles.
20" = 2.78 square feet. Now divide the area of the tiles into the area of the room. 140/2.78 = 51 tiles
640
It will take nine 330 by 330 mm tiles to cover one square meter. The room is 144 square meters in area. 9X144=1296 tiles. With a 5mm grout.
Area of room = 5' * 6' = 30 square feet. Assuming the tiles are 12 * 12 square inches (not sq cm) then the area of each tile is 1 square foot and so 30 tiles are needed.
16 square tiles
First we need to calculate the square footage of the room. 15*20 = 300 square feet Now we need to know how many square feet each tile covers. 20" = 1.667~ square feet 1.6672 = 2.78 square feet. Now we divide the area of the tiles into the area of the room. 300/2.78 = 108 tiles. This gives the exact number of tiles you need mathematically. Realistically you need to account for cutting and breaking. It's safe to round that up to 120 tiles.
123 tiles
375
The answer will depend on the shape of the 168 square feet. The best that you can do, leaving no room for grout, is 42 tiles. However, if the area is circular, you will require more.
291.43 tiles
13 feet by 12 feet is the same as 156 inches by 144 inches. Multiply 156 by 144 to find that the room's area is 22464 square inches. Next, find the area of each tile by multiplying 13 by 13 to get 169 square inches. We need to find how many 169 square inch tiles can fit in a 22464 square inch room, so divide 22464 by 169 and get 132.923077. Round that up to the nearest whole number and get:133 tiles.
There is not sufficient information to answer the question. Saying that the room is 200 foot long conveys no information at all on its width and, therefore, on the area that needs to be covered by the tiles.