Question

If A = {1, 2, 5} and B = {3, 4, 5, 9}, then $A\Delta B$ is equal to

• A. {1, 2, 5, 9}
• B. {1, 2, 3, 4, 9}
• C. {1, 2, 3, 4, 5, 9}
• D. None of these

Answer 1

Answer: (B)

$A\Delta B=(A-B)\cup (B-A)$
$=\{1,2\}\cup \{3,4,9\}$
$=\{1,2,3,4,9\}$