Question

If n(A)=35,n(A∩B)=25 and n(A∪B)=50 thenn(B)=? 45 42 40 44

Answer 1

Answer:

The answer is 40

Step-by-step explanation:

We know that

n(A∪B)= n(A)+n(B) - n(A∩B)

So

n(B) = 50 + 25 -35 = 40

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Answer 2

$\large\bf\underline {To \: find:-}$

• we need to find n(B)

⚘ $\huge\bf\underline{Solution:-}$

$\bf\underline{\red{Given:-}}$

● n(A) = 35

● n(A ∩ B) = 25

● n(A ∪ B) = 50

● n(B) = ?

• By using formula :-

$\red {\bf{n(A \cup \: B) +n( A \cap \: B) = n(A) + n(B)}}$

⇝ n(B) = n(A ∩ B) + n(A ∪ B) - n(A)

• n(A) = 35
• n(A ∩ B) = 25
• n(A ∪ B) = 50

Now ,

▶ putting all these values in formula :-

⇝ n(B) = 25 + 50 - 35

⇝ n(B) = 75 - 35

⇝ n(B) = 40

Hence,

Number of elements in set B is 40.

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