1. Tardigrade
  2. Question
  3. Mathematics
  4. Let A and B are two sets having 3 elements in common. If n(A)=5 and n(B)=4, then n[(A × B) ∩(B × A)] is equal to

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. Let $A$ and $B$ are two sets having 3 elements in common. If $n(A)=5$ and $n(B)=4$, then $n[(A \times B) \cap(B \times A)]$ is equal to

Relations and Functions

Solution:

Given, $n(A)=5, n(B)=4, n(A \cap B)=3$
$n[(A \times B) \cap(B \times A)] $
$ =n[(A \cap B) \times(B \cap A)] $
$ =n(A \cap B) \times n(B \cap A)[\because n(A \cap B)=n(B \cap A)] $
$ =3 \times 3=9$