If X ∪ {3, 4} = {1, 2, 3, 4, 5, 6} the which of the following is true (a) Smallest set X = {1, 2, 5, 6} (b) Smallest set X = {1, 2, 3, 5, 6}

Question

If X ∪ {3, 4} = {1, 2, 3, 4, 5, 6}  the which of the following is true

(a) Smallest set X = {1, 2, 5, 6}

(b) Smallest set X = {1, 2, 3, 5, 6}

(c) Smallest set X = {1, 2, 3, 4}

(d) Greatest set X = {1, 2, 3, 4}

Answer 1

(a) Smallest set X = {1, 2, 5, 6}

EXplaination:
X ∪ {3, 4} = {1, 2, 3, 4, 5, 6}
Then the Smallest set of X will be X ∪ {3, 4} – {3, 4} i.e. {1, 2, 3, 4, 5, 6} – {3, 4} = {1, 2, 5, 6}.