Question

Let $U=\{1,2,3,4,5,6,7,8,9\}$ and $A$ be the set of all multiples of $3$ in $U$. Find $A^{\prime }$ and $U$

Answer 1

Given : $U=\{1,2,3,4,5,6,7,8,9\}$

Let $A$ be the set af all multiples of $3$ in $U$.

We observe $A=\{3,6,9\}$.

If we remove these from $U$, the remaining elements are $1,2,4,5,7,8$.

In the figure, the shaded portion shows $A^{\prime }$

Hence $A^{\prime }=\{1,2,4,5,7,8\}$.