Question

What is the value of the expression 8p4

Answer 1

ANSWER

$8P_4 = 1680$

EXPLANATION

We use the formula

$nP_r = \frac{n!}{(n - r)!}$

For

$8P_4$

and n=8, r=4.

$8P_4= \frac{8!}{(8- 4)!}$

This simplifies to

$8P_4= \frac{8!}{4!}$

We expand the numerator using factorial notation,

$8P_4= \frac{8 \times 7 \times 6 \times 5 \times 4!}{4!}$

The common factors cancel out.

$8P_4= 8 \times 7 \times 6 \times 5$

$8P_4= 1680$