Finite Math Examples

${}_{5}P_{20}$

Step 1

Evaluate ${}_{5}P_{20}$ using the formula ${}_{n}P_{r} = \frac{n!}{(n - r)!}$ .

$\frac{5!}{(5 - 20)!}$

Step 2

Since $r > n$ , it is impossible to select $20$ items from a total of only $5$ possible items.

$0$