Chapter 11.6, Problem 28E

To determine

To calculate: the probability to guess the password of Sonia in first try.

Answer to Problem 28E

the probability to guess the password of Sonia in first try is $\frac{1}{120}$ .

Explanation of Solution

Given :

Total alphabets in Sonia name = 5

Formula used:

  $n!=n·\left(n-1\right)·\mathrm{.....1}$

Calculation : the total possibilities of her password is-

  $\begin{array}{l}5!=5·4·3·2·1\text{ [subtitute n by 5]}\\ \text{5!=120 [multiply]}\end{array}$

To find the probability divide the no of try by total possibility,

Probability = $\frac{1}{120}$

Hence,the probability to guess the password of Sonia in first try is $\frac{1}{120}$ .