Q. Let $X$, $Y$, $Z$ be subsets of $U$, where $n(U) = 35$, $n(X) = 15$, $n(Y) = 22$, $n(Z) = 14$ and $n(X \cap Y) = 11$, $n(Y \cap Z) = 8$, $n(X \cap Z) = 5$, $n(X \cap Y \cap Z) = 3$ then $n(X \cup Y \cup Z)'$ equals
Sets
Solution: