Question

For any three sets $A=\{1,2,3\}$
$B=\{2,3,4\},C=\{1,2,3,4,5\};A\cup B=$ $\&A\cup B\cup C=$

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

Answer 1

Answer: (A), (C)

$\{1,2,3,4,5\}$

Given three sets $A=\{1,2,3\}$
$B=\{2,3,4\},C=\{1,2,3,4,5\}$

Now, $A\cup B=\{1,2,3\}\cup \{2,3,4\}=\{1,2,3,4\}$

Also, $A\cup B\cup C=\{1,2,3,4\}\cup \{1,2,3,4,5\}$
$\Rightarrow A\cup B\cup C=\{1,2,3,4,5\}$