Question

Compute P7,2. (Enter an exact number.)

Answer 1

Answer:

42

Step-by-step explanation:

The permutation formula is P(n, r) = n! / (n - r)!. We know that n = 7 and r = 2 so we can write:

7! / (7 - 2)!

= 7! / 5!

= 7 * 6 * 5 * 4 * 3 * 2 * 1 / 5 * 4 * 3 * 2 * 1

= 7 * 6 (5 * 4 * 3 * 2 * 1 cancels out)

= 42

Answer 2

Answer:

$\boxed{42}$

Step-by-step explanation:

Apply the permutation formula.

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

$P=number \: of \: permutations\\n=total \: number \: of \: objects \: in \: the \: set\\r=number \: of \: choosing \: objects \: from \: the \: set$

$n=7\\r=2$

Plug in the values and evaluate.

$P(7,2)=\frac{7!}{ (7-2)!}$

$P(7,2)=\frac{7!}{ (5)!}$

$P(7,2)=\frac{5040}{120}$

$P(7,2)=42$