Chapter 7, Problem 16PTTS

To determine

To find: The number of times of roll a $4$ .

Answer to Problem 16PTTS

The number of times of roll a $4$ is 20.

Explanation of Solution

Given information: You rolled a number cube $20$ times. You found the experimental probability of rolling a number less than $4\text{ to be 0}\text{.7}$ . You rolled each of the numbers $4,5\text{ and 6}$ the same number of times. How many times did you roll a $4$ .

Calculation:

If a cube is being thrown the elements we get getting in the sample space is,

  $\text{s =}\left\{1,2,3,4,5,6\right\}$

Hence, $\text{n(s)=6}$

Odd number less then $3$

  $=\left\{1,2,3\right\}$ and The events $=\left\{1,2,3\right\}$

Hence, $\text{n(E)=3}$

Let, $4$ has been rolled $x$ times.

  $x=20$

Hence, The number of times of roll a $4$ is 20.