Question

Let $A=\{1,2,3,4\}$ and $B=\{2,3,4,5,6\}$, then $A△B$ is equal to =?$($ where $A△B$ is defined as $A△B=\{x:x\in \frac{A}{B}$ or $x\in \frac{B}{A}\left\}\right)$

• A. $\{2,3,4\}$
• B. $\left\{1\right\}$
• C. $\{5,6\}$
• D. $\{1,5,6\}$

Answer 1

Answer: (D)

$\{1,5,6\}$

$A\Delta B=(A\cup B)-(A\cap B)$
$=\{1,2,3,4,5,6,\}-\{2,3,4\}$
$=\{1,5,6\}$