Lindsay,
I do believe it was exactly the same question. The sentence you asked about was "Здесь три белые тарелки." And "тарелка" is feminine. Then some other people and I explained that both versions are possible for the feminine nouns: "три белые тарелки" and "три белых тарелки" are both OK.
The same as "две глубокие тарелки" and "две глубоких тарелки" are possible.