Question

Let A and B be two sets such that n (A) = 16, n(B) = 14, $n(A\cup B)$= 25. Then, $n(A\cap B)$ is equal to .

• A. 30
• B. 50
• C. 5
• D. none of these

Answer 1

The correct option is C

5

We know :

$n(A\cup B)=n\left(A\right)+n\left(B\right)-n(A\cap B)$

Now,

$n(A\cap B)=n\left(A\right)+n\left(B\right)-n(A\cup B)$

= 16+14-25

= 5