a small hotel is interested in the pattern above for its square shaped reception area.How many dark-coloured tiles would be needed if there would be 18 tiles on each side?
THE PATTERN
There are 3 designs of tiles.The first design have total 9 tiles and 4 dark tiles.The second design have total 16 tiles and 8 dark tiles.The third design have total 25 tiles and 12 dark tiles.
PLEASE HELP ME FOR THIS