Q3 of 145 Page 43

If A and B are two sets such that n(A) = 24, n(B) = 22 and n(A ∩ B) = 8, find:

(i) n(A ∪ B)


(ii) n(A – B)


(iii) n(B – A)


Given:


n(A) = 24, n(B) =22 and n(A ∩ B) = 8


To Find:


(i) n(A ∪ B)


n(A ∪ B) = n(A) + n(B) – n(A ∩ B)


= 24 + 22 – 8


= 38


Therefore,


n(A ∪ B) = 38


(ii) n(A - B)


We know that,


n(A - B) = n(A) – n(A ∩ B)


= 24 – 8


= 16


Therefore,


n(A - B) = 16


(iii) n(B - A)


We know that,


n(B - A) = n(B) – n(A ∩ B)


= 22 – 8


= 14


Therefore,


n(B - A) = 14


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