Question

The Cartesian product $P\times P$ has $16$ elements among which two elements are $(a,b)$ and $(c,d)$. Find the set $P$ and the remaining elements of $P\times P$

Answer 1

If $P$ has n elements then the cartesian product of $P\times P$ has $2^n$ elements.

By using this $P$ has 4 elements and we can see all those 4 in given question;

$P=\{a,b,c,d\}$