Mathematics
If n(A - B) = 24, n(B - A) = 32 and n(A ∩ B) = 10; find n(A ∪ B).
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Answer
n(A - B) = 24
n(B - A) = 32
n(A ∩ B) = 10
∴ n(A - B) = n(A) - n(A ∩ B)
Putting the values, we get
24 = n(A) - 10
n(A) = 24 + 10
n(A) = 34
∴ n(B - A) = n(B) - n(A ∩ B)
Putting the values, we get
32 = n(B) - 10
n(B) = 32 + 10
n(B) = 42
∴ n(A ∪ B) = n(A) + n(B) - n(A ∩ B)
Putting the values, we get
n(A ∪ B) = 34 + 42 - 10
⇒ n(A ∪ B) = 76 - 10
⇒ n(A ∪ B) = 66
∴ n(A ∪ B) = 66
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