144/2.25=64. 18x18 tile cover 2.25 sq ft area.
The answer depends on the measurement units used for 18x18.
The best way to figure out how many 13x13 tile will be needed to cover 30 sf of floor is to calculate 13x13/144 give coverage per tile (1.1736), then take 30/1.736 = 25.56 tiles.
4 to 5.00 per sf
18 inches = 1.5 ft, so each tile is 2.25 sq ft, number required = 249/2.25 = 111
2.25 square feet
It is not clear what is meant by an "18x18 square feet" tile. 18ft * 18 ft = 324 square feet, so that one tile will be more than enough. An 18 inch by 18 inch tile cannot be a 18x18 square feet tile.
144/2.25=64. 18x18 tile cover 2.25 sq ft area.
You would need 800 tile assuming you had no waste at all. Since this is unlikely you will need 825 tile.
The diagonal of an 18x18 tile is 18*sqrt(2) = 25.46 units.
Assuming 18x18 refers to 18inch*18inch and not some other measure, each tile is 1.5'*1.5' = 2.25 sq ft So number of tiles required = 150/2.25 = 66.66... ie 67 tiles. That is the mathematical answer. However, this assumes that the 150 sq ft area is a "well behaved" shape and that there are few awkward curves and corners around which the tiles have to be fitted. In real life it is sensible to allow for 10% wastage.
160 of them.
It would take approximately 311 tiles plus 5% to 10% waste depending on how you lay your floor out and how many cuts you will have.
To cover 720 sq feet of floor with 18" x 18" tile, you would need 320 tiles.
There are 2.25 square feet in 1 18" x 18" tile. Counting for NO waste, you would been 71 tile. Since tile this large with surely have some waste you will want to buy around 78 tile.
i thinking the room is 17' 6" x 18' to equal 315 sqftbut you still only need 315 ....12" x 12" tilePlus you need to add waste so you need to make the size 18x18 which is 324 sf. of 12x12 tiles
18 inches = 1.5 foot18" x 18" = 1.5-ft x 1.5-ft = 2.25 square feet