Question

If two sets $P$ and $Q,n\left(P\right)=5,n\left(Q\right)=4$ then $n(P\times Q)=$

• A. $20$
• B. $9$
• C. $25$
• D. $5/4$

Answer 1

The correct option is A $20$

$\begin{array}{cc}n(P\times Q)& =n\left(P\right)\times n\left(Q\right)\\ & =5\times 4\\ & =20\end{array}$

$\therefore$ option $A$ is correct.