# A discrete mathematics problem by Zandra Vinegar

If $$|X^C \cup Y^C \cup Z^C| = 20$$ and $$|(X^C \cup Y^C \cup Z^C)^C| = 10$$ and $$|X\cap Y| = 15$$, then $$|(X\cap Y)^C| = ?$$

Details:

$$|S|$$ represents the cardinality of the set $$S$$ and $$S^C$$ represents the complement of the set $$S$$.

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