If the set $A$ contains 5 elements and the set $B$ contains 6 elements, then the number of one-one and onto mappings from $A$ to $B$ is

0

The correct answer is Option (3) → 0 ##

We know that, if $A$ and $B$ are two non-empty finite set containing $m$ and $n$ elements respectively, then the number of one-one and onto mapping from $A$ to $B$ is

$\begin{cases} n!, & \text{if } m = n \\ 0, & \text{if } m \neq n \end{cases}$

Given that, $m = 5$ and $n = 6$

$∴m \neq n$

Number of mapping = 0