Chapter 6.7, Problem 22E

To determine

To find : the probability of waiting more than 10 minutes for the train.

Answer to Problem 22E

The probability to wait for more than 10 minutes for the train is $\frac{1}{\text{3}}$ .

Explanation of Solution

Given information :

the train runs every 15 minutes.

Calculation :

Here, to wait for more than 10 minutes, arrive in the 5 minute following the departure of the train.

So, the number of success over here is 5 and number of trials is 15.

Thus, the probability to wait for more than 10 minute for the train is

  $\begin{array}{l}P\left(\text{Wait more than 10 minutes}\right)=\frac{\text{Number of success}}{\text{Number of trials}}\\ P\left(\text{Wait more than 10 minutes}\right)=\frac{5}{\text{15}}\\ P\left(\text{Wait more than 10 minutes}\right)=\frac{1}{\text{3}}\end{array}$

Hence,

The probability to wait for more than 10 minutes for the train is $\frac{1}{\text{3}}$ .