use the venn diagram to determine n(a). n(a) = □

Explanation:

Step1: Define complement set

$A'$ is the set of all elements in the universal set $U$ that are not in $A$.

Step2: Sum non - A elements

We sum the elements in the regions outside of circle $A$. The elements outside of $A$ are $3$, $4$, $9$ and $14$. So $n(A')=3 + 4+9 + 14$.

Step3: Calculate the sum

$3+4 + 9+14=30$.

Answer:

$30$