Question

If n(U) = 40, n(A) = 35 and n(B) = 20, then the least value of n(A ∩ B), where U is an universal set, is
a)Zero
b)15
c)20
d)35

Answer 1

Answer:

     B)15

Step-by-step explanation:

n(A∩B)=n(A)+n(B)-n(U)

        ==> 35+20-40

        ==> 55-40

        ==> 15

Answer 2

Given:

n(U) = 40

n(A) = 35

n(B) = 20

To Find:

n(A ∩ B)

Solution:

The formula to find n(A∩B)

n(A ∩ B) = n(A) + n(B) - n(U)

n(A ∩ B) = 35 + 20 - 40

n(A ∩ B) = 55-40

n(A ∩ B) = 15 (Option b)

The least value of n(A ∩ B), where U is a universal set, is 15. Thus the answer is option (b).