Question

3.
If n(A) denotes the number of elements in set A and if n(A) = 4, n(B) = 5 and n(A n B) = 3 then
n[(A x B) n (B x A)] =
(1) 8
(2) 9
(3) 10
(4) 11​

Answer 1

Answer:

A=4,B=5,n(AnB)=3

n(3)×(3)

=9