Question

If A and B be non-empty sets having n elements in common, then the number of elements common to $A\times BandB\times A$ is

• A. n
• B. 2n
• C. $n^2$
• D. 0

Answer 1

The correct option is C

$n^2$

Number of elements common to $A\times B$ and $B\times A$ is $n^2$