The answer depends on the shape of the 30 square feet area. If it is in the form of a strip that is 5 inches wide and 72 feet long and you don't want mosaics with little offcuts, then you will require 144 tiles.
875 24-inch tiles.
225 16-inch tiles.
5,184 2-square-inch tiles are needed.
297 16x16-inch tiles.
18 10x10-inch tiles.
125 16-inch tiles.
236 18-inch tiles.
113 tiles
You'll need 200 18-inch tiles.
54 4x4-inch tiles.
61 whole tiles represent 1421/3 square feet 144 square feet works out to 61.714 tiles (rounded)
864 tiles.144 tiles per square foot.