Question

If A = {3, 6, 9, 12, 15, 18, 21}, B = {4, 8, 12, 16, 20}, C = {2, 4, 6, 8, 10, 12, 14, 16}, D = {5, 10, 15, 20}, find :

(i) A - B (ii) A - C (iii) A - D

(iv) B - A (v) C - A (vi) D - A

(vii) B - C (viii) B - D (ix) C - B

(x) D - B (xi) C - D (xii) D - C

Answer 1

Here

A = {3, 6, 9, 12, 15, 18, 21},

B = {4, 8, 12, 16, 20},

C = {2, 4, 6, 8, 10, 12, 14, 16},

D = {5, 10, 15, 20}

(i) A - B = {3, 6, 9, 12, 15, 18, 21} - {4, 8, 12, 16, 20}

= {3, 6, 9, 15, 18, 21}

(ii) A - C = {3, 6, 9, 12, 15, 18, 21} - {2, 4, 6, 8, 10, 12, 14, 16}

= {3, 9, 15, 18, 21}

(iii) A - D = {3, 6, 9, 12, 15, 18, 21} - {5, 10, 15, 20}

= {3, 6, 9, 12, 18, 21}

(iv) B - A = {4, 8, 12, 16, 20} - {3, 6, 9, 12, 15, 18, 21}

= {4, 8, 16, 20}

(v) C - A = {2, 4, 6, 8, 10, 12, 14, 16} - {3, 6, 9, 12, 15, 18, 21}

= {2, 4, 8, 10, 14, 16}

(vi) D - A = {5, 10, 15, 20} - {3, 6, 9, 12, 15, 18, 21}

= {5, 10, 20}

(vii) B - C = {4, 8, 12, 16, 20} - {2, 4, 6, 8, 10, 12, 14, 16}

= {20}

(viii) B - D = {4, 8, 12, 16, 20} - {5, 10, 15, 20}

= {4, 8, 12, 16}

(ix) C - B = {2, 4, 6, 8, 10, 12, 14, 16} - {4, 8, 12, 16, 20}

= {2, 6, 10, 14}

(x) D - B = {5, 10, 15, 20} - {4, 8, 12, 16, 20}

= {5, 10, 15}

(xi) C - D = {2, 4, 6, 8, 10, 12, 14, 16} - {5, 10, 15, 20}

= {2, 4, 6, 8, 12, 14, 16}

(xii) D - C = {5, 10, 15, 20} - {2, 4, 6, 8, 10, 12, 14, 16}

= {5, 15, 20}