Question

Two sets $A\&B$ such that $n\left(A\right)=p$ and $n\left(B\right)=q,$ then the number of functions from $A\to B$ is , and from $B\to A$ is

Answer 1

Given two sets $A\&B$ such that
$n\left(A\right)=p\&n\left(B\right)=q$
We know that number of functions from $A\to B=n(B{)}^{n\left(A\right)}=q^p$
Similarly, the number of functions from $B\to A=p^q$