Question

If$n ( A ) = 3$, $n ( B ) = 6$ and $A \subseteq B$ .Then the number of elements in $A \cup B$ is equal to.

• A. 3
• B. 9
• C. 6
• D. None of these

Answer 1

Answer: (C)

6

Answer 2

Since $A \subseteq B , \therefore A \cup B = B$ .

So, $n ( A \cup B ) = n ( B ) = 6$.