Chapter 5, Problem T5.8SPT

To determine

To find: The probability that two students of same sex are selected.

Answer to Problem T5.8SPT

The probability is 0.49.

Explanation of Solution

Given:

Number of girls = 18

Number of boys = 14

Calculation:

The probability that two students of same sex are selected can be calculated as:

  $\begin{array}{c}P\left(\begin{array}{l}\text{Same }\\ \text{sex}\end{array}\right)=P\left(\text{Two girls}\right)+P\left(\text{Two boys}\right)\\ =\frac{18}{32}\times \frac{17}{31}+\frac{14}{32}\times \frac{13}{31}\\ =\frac{306}{992}+\frac{182}{992}\\ =0.49\end{array}$

The required probability is 0.49.

Hence, the correct option is (a).