Question

2
2.
if n(U)=200,n(A)=160, N(B)=80,then least value of AU B is
a.160
b.240 c.80
d.200
a
b
С​

Answer 1

n(U)=200

n(A)=160

n(B) =80

n(AUB)=?

We know that :-

n(AUB) =n(A)+n(B) -n (A∩B)

For least value of n(AUB) ,it is clear that  n(A ∩ B) should be maximum .

Here maximum value of n(A ∩ B) = 80.  (B is to be a subset of A so intersection will have maximum value of 80)

∴n(AUB)=160+80–80= 160

Answer:- a. 160