Question 28 of 47beginner🔧 ApplyShort Answer4 marks
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
Answer
{3, 6, 9, 15, 18, 21}
(ii)
A – C
Answer
{3, 9, 15, 18, 21}
(iii)
A – D
Answer
{3, 6, 9, 12, 18, 21}
(iv)
B – A
Answer
{4, 8, 16, 20}
(v)
C – A
Answer
{2, 4, 8, 10, 14, 16}
(vi)
D – A
Answer
{5, 10, 20}
(vii)
B – C
Answer
{20}
(viii)
B – D
Answer
{4, 8, 12, 16}
(ix)
C – B
Answer
{2, 6, 10, 14}
(x)
D – B
Answer
{5, 10, 15}
(xi)
C – D
Answer
{2, 4, 6, 8, 12, 14, 16}
(xii)
D – C
Answer
{5, 15, 20}
Explanation
This question tests the concept of difference of sets. The difference of two sets X – Y represents all elements that belong to set X but do NOT belong to set Y. To solve each part, we identify elements common to both sets (intersection) and then exclude them from the first set. For example, in A – B, the only common element is 12, so we remove 12 from A to get {3, 6, 9, 15, 18, 21}.