If n(U) = 20, n(A)=12, n(B)=9, where U is the universal set, then
17
9
11
3
As we learnt
UNION OF SETS -
Let A and B be any two sets. The union of A and B is the set which consists of all the elements of A and all the elements of B, the common elements being taken only once. The symbol ‘∪’ is used to denote the union.
- wherein
Symbolically, we write A U B = {x: x ∈ A or x ∈ B}.
n(A U B) = n(A) + n(B) - n(AB)
=12+9-4=17
n(A U B)'=20-17=3
Option 1)
17
Option 2)
9
Option 3)
11
Option 4)
3
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