Question

A die is rolled. What is the probability that the number is a factor of 6 or more than 2? Does this scenario represent mutually exclusive or mutually inclusive events?

Answer 1

Factors of 6 are : 1,2,3 and 6.

Let us find probability of getting the number that is a factor of 6.

$P(\text{ The number is a factor of 6})=\frac{4}{6} =\frac{2}{3}$

Now let us find probability of getting a number more than 2 (3,4,5,6).

$P(\text{ The number is a greater than 2})=\frac{4}{6} =\frac{2}{3}$

We can see that these two events are mutually inclusive events. We can find probability of mutually inclusive events by formula $P(\text{X or Y})=P(X)+P(Y)-P(\text{X and Y})$.  

$P(\text{ The number is a factor of 6 and greater than 2})=\frac{2}{6} =\frac{1}{3}$

Now we will find probability of getting the number is a factor of 6 or more than 2 using above formula.

$P(\text{ The number is a factor of 6 or greater than 2})=\frac{2}{3} +\frac{2}{3}-\frac{1}{3}$    

$P(\text{ The number is a factor of 6 or greater than 2})= \frac{4}{3}-\frac{1}{3}=\frac{3}{3}=1$  

Therefore, our probability will be 1 and this scenario represents mutually inclusive events.