Question

27. If A and B are two finite sets such that n(A) = 40,
n(B) = 80 and n(AUB) = 90, then find n(
A B ).
A. 20
C. 40
B. 30
D. 45​

Answer 1

Answer:

n(AB)=120 please mark brain list

Answer 2

The value of n(A ∩ B) is "B) 30".

Step-by-step explanation:

Given,

n(A) = 40,  n(B) = 80 and n(A U B) = 90

To find, the value of n(A ∩ B) = ?

We know that,

n(A U B) = n(A) + n(B) - n(A ∩ B)

⇒ n(A ∩ B) = n(A) + n(B) - n(A U B)

∴ n(A ∩ B) = 40 + 80 - 90

= 120 - 90

= 30

∴ n(A ∩ B) = 30

Hence, the value of n(A ∩ B) is "B) 30".