Practice By Tag: Counting Functions

Question: 2013 Fall Midterm - 1

1 . Let $A$ be a set of size 3 and let $B$ be a set of size 4. How many one-to-one functions $f: A \rightarrow B$ are there?

(a)

$\frac{4!}{1!}$

(b)

$\frac{4!}{0!}$

(c)

$\frac{1!}{4!}$

(d)

$\frac{3!}{2!}$