The pattern of tiles is "Blue, White, Black," which consists of 3 tiles.
To determine how many complete cycles of the pattern are in 85 tiles, we divide 85 by 3:
In each complete cycle of 3 tiles, there is 1 black tile. So, the number of black tiles from the complete cycles is:
Now we consider the extra tile. The first tile in the repeating pattern is blue. So the additional tile does not add to the count of black tiles.
Thus, the total number of black tiles used is:
Therefore, the final answer is:
28