Question

If OA and B be two sets such that n(A)=75. n(B)=65 and n(A cap B ) =45
1. find n(A UB )
2 .find n(A-B)​

Answer 1

Step-by-step explanation:

n(A ∩ B)

n(A) = 75, n(B) = 65 and n(A ∩ B) = 45

(i) We know that,

n( A ∪B) = n(A) + n(B) – n( A ∩ B)

n(A ∪B) =75 + 65 – 45

n(A∪B) = 140 - 45 = 95

(ii) We know that,

n(A – B) = n(A) – n(A ∩ B)

n(A – B) = 75 – 45 = 30

(iii) We know that,

n(B – A) = n(B) – n(A ∩ B)

n(B – A) = 65 – 45 = 20