Question

Use the given figure to find $n(A$ ${}^{{}^{\prime }}$ $)$
Given, $n($ $\xi$ $)=52$, $n\left(A\right)=43$ and $n\left(B\right)=27$.

Answer 1

Given, $n($ $\xi$ $)=52$, $n\left(A\right)=43$

$n\left(A^{{}^{\prime }}\right)$ will have the elements outside $A$.
$\Rightarrow n\left(A^{{}^{\prime }}\right)=\xi -n\left(A\right)=52-43=9$