Let $A$, $B$, and $C$ be three sets with the following cardinalities: $n(A) = 20$, $n(B) = 25$, $n(C) = 30$. \nIt is known that $n(A \cup B \cup C) = 50$. \nAlso, $n(A \cap B) = 10$ and $n(B \cap C) = 12$. \nWhat is the range of possible values for $n(A \cap C)$?