Question

If $A=(6,7,8,9),B=(4,6,8,10)$ and $C=\{x:xϵN:2<x\le 7\}$ ; find : $B-B$

• A. $\varphi$
• B. $\left\{0\right\}$
• C. $\{6,7\}$
• D. $\left\{4\right\}$

Answer 1

The correct option is A $\varphi$

Given : $A=(6,7,8,9),B=(4,6,8,10)$ and $C=\{x:xϵN:2<x\le 7\}$

$B-B$ will always be a null set it will contain elements of $B$ which are not in $B$ i.e. no elements.
So, $B-B=\varphi$