যদি n(A∪B) = 61, n(A) = 30, n(B) = 54 হয় তাহলে n(A∩B) এর মান কত?

A 22

B 25

C 23

D 27

Correct Answer: Option C

n(A U B) = n(A) + n(B) - n(A ∩ B). n(A ∩ B)= n(A) + n(B) - n(A U B) so, n(A ∩ B)= (30 +54)-61 =23