If A and B are disjoint, then n(A B) is equal to - Vidyadip

MCQ

If $A$ and $B$ are disjoint, then $n(A \cup B)$ is equal to

A
$n(A)$
B
$n(B)$
✓
$n(A) + n(B)$
D
$n(A)\,.\,n(B)$

✓

Answer

Correct option: C.

$n(A) + n(B)$

c
(c) Since $A$ and $B$ are disjoint, $\therefore A \cap B = \phi $

$n(A \cap B) = 0$

Now $n\,(A \cup B) = n(A) + n(B) - n(A \cap B)$

$ = n(A) + n(B) - 0$$ = n(A) + n(B)$.

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