Chapter 12.7, Problem 50MR

To determine

To find: The number of permutations or combinations.

Answer to Problem 50MR

The solution is $840$ .

Explanation of Solution

Given:

The given term is,

  $P{}_4$

Calculation:

For any positive integers,

  $P{}_r=\frac{n!}{\left(n-r\right)!}$

The value is calculated as,

  $\begin{array}{c}P{}_4=\frac{7!}{\left(7-4\right)!}\\ =\frac{7\times 6\times 5\times 4\times 3!}{3!}\\ =840\end{array}$

Therefore, the solution is $840$ .