Chapter 12.8, Problem 34PPE

To determine

To find: The probability that you are chosen on Monday and Terry is chosen on Tuesday.

Answer to Problem 34PPE

The required probability is $\frac{1}{20}$ .

Explanation of Solution

Given:

There are3 friends are chosen out of 5 names.

Calculation:

The first outcome affects the probability of the second so the events are dependent.

Find the probability that you chosen on Monday.

  $P\left(\text{you}\right)=\frac{1}{5}$

Find the probability that Terry chosen after you.

  $P\left(\text{Terry}\text{after}\text{you}\right)=\frac{1}{4}$

Find the required probability as follows.

  $\begin{array}{c}P\left(\text{you}\text{then}\text{Terry}\right)=P\left(\text{you}\right)\times P\left(\text{Terry}\right)\\ =\frac{1}{5}\times \frac{1}{4}\\ =\frac{1}{20}\end{array}$

Therefore, the required probability is $\frac{1}{20}$ .