A marble is selected from a bag containing eight marbles numbered 1 to 8. The number on the marble selected will be recorded as the outcome.

Consider the following events:

Event [tex]A[/tex]: The marble selected has a number less than 4.

Event [tex]B[/tex]: The marble selected has an even number.

Give the outcomes for each of the following events. If there is more than one element in the set, separate them with commas.

(a) Event "[tex]A[/tex] and [tex]B[/tex]": \{\square\}

(b) Event "[tex]A[/tex] or [tex]B[/tex]": \{\square\}

(c) The complement of the event [tex]B[/tex]: \{\square\}



Answer :

Let's break down the problem and look at each event step by step.

Event [tex]$A$[/tex]: The marble selected has a number less than 4.
The numbers on the marbles in this event are: {1, 2, 3}

Event [tex]$B$[/tex]: The marble selected has an even number.
The numbers on the marbles in this event are: {2, 4, 6, 8}

Now, let's determine the outcomes for each specified event:

### Part (a) Event \"[tex]$A$[/tex] and [tex]$B$[/tex]\":

We need to find the marbles that satisfy both event [tex]$A$[/tex] and event [tex]$B$[/tex]. In other words, we are looking for numbers that are both less than 4 and even. From the events, we get:
- Event [tex]$A$[/tex] numbers: {1, 2, 3}
- Event [tex]$B$[/tex] numbers: {2, 4, 6, 8}

The intersection of these sets (common elements) is: {2}.

Outcome for event " [tex]$A$[/tex] and [tex]$B$[/tex] " is {2}.

### Part (b) Event \"[tex]$A$[/tex] or [tex]$B$[/tex]\":

We need to find the marbles that satisfy either event [tex]$A$[/tex] or event [tex]$B$[/tex]. This includes all numbers that are either less than 4 or even. To do this, we take the union of both events:
- Event [tex]$A$[/tex] numbers: {1, 2, 3}
- Event [tex]$B$[/tex] numbers: {2, 4, 6, 8}

Combining these sets (without repeating elements) gives us: {1, 2, 3, 4, 6, 8}.

Outcome for event " [tex]$A$[/tex] or [tex]$B$[/tex] " is {1, 2, 3, 4, 6, 8}.

### Part (c) The complement of the event [tex]$B$[/tex]:

The complement of event [tex]$B$[/tex] consists of all marbles that are not in event [tex]$B$[/tex]. This means we want numbers that are not even (i.e., odd numbers).
- Event [tex]$B$[/tex] numbers: {2, 4, 6, 8}

The numbers in the total set {1, 2, 3, 4, 5, 6, 7, 8} that are not in event [tex]$B$[/tex] are: {1, 3, 5, 7}.

Outcome for the complement of event [tex]$B$[/tex] is {1, 3, 5, 7}.

To summarize:

(a) Event " [tex]$A$[/tex] and [tex]$B$[/tex] " is {2}.

(b) Event " [tex]$A$[/tex] or [tex]$B$[/tex] " is {1, 2, 3, 4, 6, 8}.

(c) The complement of the event [tex]$B$[/tex] is {1, 3, 5, 7}.