Question

1) If n (A) =10 , n (B) =20 , n (A U B) =25 then find n (A ∩ B).

Answer 1

Answer:

5

Step-by-step explanation:

n(A U B) = n(A) +n(B) -n (A ∩ B)

25 =10 +20 -n (A ∩ B)

25-30 =-n (A ∩ B).

-5 =-n (A ∩ B).

change the LHS into RHS

n (A ∩ B)=5