Question

If A\B = {a, b}, B\A = {c, d} and A\B = {e, f}, then the set B is equal to

• A. {a, b, c, d}
• B. {e, f, c, d}
• C. {a, b, e, f}
• D. {c, d, a, e}

Answer 1

Answer: (B)

{e, f, c, d}

Answer 2

Given, $A / B =\\{a, b\\}$
$B / A=\\{C, d\\}$
and $A \cap B=\\{e, f\\}$
$\therefore A-B=\\{a, b\\}\,....(i)$
$B-A=\\{c, d\\}\,....(ii)$
and $A \cap B=\\{e, f\\} \,...(iii)$
$\therefore$ From Eqs. (i), (ii) and (iii), we get
$B=\\{c, d, e, f\\}$