Question

If $A$ and $B$ are disjoint sets, then $n(A\cup B)$ is

• A. $n\left(A\right)+n\left(B\right)$
• B. $n\left(A\right)\times n\left(B\right)$
• C. $\frac{n\left(A\right)+n\left(B\right)}{2}$
• D. $\sqrt{n\left(A\right)\cdot n\left(B\right)}$

Answer 1

The correct option is A $n\left(A\right)+n\left(B\right)$

A and B are disjoint. So $A\cap B=\varnothing$.