Chapter 0.5, Problem 7E

To determine

To evaluate: the given permutation.

Answer to Problem 7E

  $P{}_5=126$ .

Explanation of Solution

Given information:

  $P{}_5$

Solving the given permutation,

  $\begin{array}{c}P{}_5=\frac{9!}{5!\left(9-5\right)!}\\ =\frac{9!}{5!4!}\\ =\frac{9\times 8\times 7\times 6\times 5\times 4\times 3\times 2\times 1}{5\times 4\times 3\times 2\times 1\times 4\times 3\times 2\times 1}\\ =\frac{9\times 8\times 7\times 6}{4\times 3\times 2\times 1}\\ =126\end{array}$

So,

After evaluating,

  $P{}_5=126$ .