Chapter 6.7, Problem 3E

To determine

To find: the probability of the event of rolling a number which is a prime number.

Answer to Problem 3E

The probability of rolling a prime number is $\frac{\text{1}}{\text{2}}$ .

Explanation of Solution

Given information :

A number cube is rolled and the favourable outcome is a prime number.

Calculation :

Total number of possible outcome in rolling a number cube is 6 i.e. 1, 2, 3, 4, 5, and 6. Also

Total number of prime number 2, 3, and 5 so total number of favourable outcome is 3.

Now,

  $\begin{array}{l}P\left(\text{Rolling Prime Number}\right)=\frac{\text{Number of favouarable outcome}}{\text{Number of possible outcome}}\\ P\left(\text{Rolling Prime Number}\right)=\frac{\text{3}}{\text{6}}\\ P\left(\text{Rolling Prime Number}\right)=\frac{\text{1}}{\text{2}}\end{array}$

Hence,

The probability of rolling a prime number is $\frac{\text{1}}{\text{2}}$ .