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CBSE - Class 11 Mathematics Probability Worksheet
EXERCISE 14.1
Two dice are thrown. The events A, B and C are as follows:
A: getting an even number on the first die.
B: getting an odd number on the first die.
C: getting the sum of the numbers on the dice ≤ 5.
state true or false: (give reason for your answer) (iii) $A = B'$
Two dice are thrown. The events A, B and C are as follows:
A: getting an even number on the first die.
B: getting an odd number on the first die.
C: getting the sum of the numbers on the dice ≤ 5.
state true or false: (give reason for your answer) (ii) A and B are mutually exclusive and exhaustive
Two dice are thrown. The events A, B and C are as follows:
A: getting an even number on the first die.
B: getting an odd number on the first die.
C: getting the sum of the numbers on the dice ≤ 5.
state true or false: (give reason for your answer) (i) A and B are mutually exclusive
Worksheet Answers
Solution:
When two six-sided dice are tossed, the sample space $S$ consists of all ordered pairs $(x, y)$, where $x$ represents the result of the first die and $y$ represents the result of the second die. The total number of outcomes is $6 \times 6 = 36$.
$S = \{ (1,1), (1,2), \dots, (6,6) \}$
Event A: Getting an even number on the first die.
$A = \{ (x, y) \in S : x \in \{2, 4, 6\} \}$
$A = \{ (2,1), (2,2), (2,3), (2,4), (2,5), (2,6), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6) \}$
Event B: Getting an odd number on the first die.
$B = \{ (x, y) \in S : x \in \{1, 3, 5\} \}$
$B = \{ (1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6) \}$
In set theory, "A or B" corresponds to the union of sets $A$ and $B$, denoted as $A \cup B$. This set contains all elements that are in $A$, in $B$, or in both [Per the Definition of Union in Probability Theory].
$A \cup B = \{ \omega : \omega \in A \text{ or } \omega \in B \}$
Since the first die must be either even $\{2, 4, 6\}$ or odd $\{1, 3, 5\}$, and every integer from 1 to 6 falls into one of these two categories, the union covers the entire sample space $S$.
| Die 1 | Die 2 (Possible outcomes) |
|---|---|
| 1 | 1, 2, 3, 4, 5, 6 |
| 2 | 1, 2, 3, 4, 5, 6 |
| 3 | 1, 2, 3, 4, 5, 6 |
| 4 | 1, 2, 3, 4, 5, 6 |
| 5 | 1, 2, 3, 4, 5, 6 |
| 6 | 1, 2, 3, 4, 5, 6 |
Because $A \cap B = \emptyset$ (the first die cannot be both even and odd simultaneously) and $A \cup B = S$, the event "A or B" represents the Certain Event, as the first die will necessarily yield either an even or an odd number.
Final Solution: The event "A or B" is equal to the sample space S, containing all 36 possible outcomes of throwing two dice.
Solution:
The experiment consists of tossing a fair, six-faced die. The sample space $S$ is defined as the set of all possible outcomes. Since a standard die has faces numbered 1 through 6, the sample space is:
$S = \{1, 2, 3, 4, 5, 6\}$
[Per the Classical Definition of Probability, the total number of outcomes $n(S) = 6$.]
Event $A$ is defined as the occurrence of a "number less than 7." We must identify all elements $x \in S$ such that $x < 7$.
By set notation, event $A$ is a subset of the sample space $S$ [By the definition of an event as a subset of the sample space].
$A = \{1, 2, 3, 4, 5, 6\}$
Since every outcome in the sample space satisfies the condition of being less than 7, event $A$ is equivalent to the sample space itself.
[In probability theory, such an event is classified as a Sure Event or a Certain Event because $A = S$.]
Final Solution: The event A is {1, 2, 3, 4, 5, 6}.
Solution:
When three unbiased coins are tossed simultaneously, each coin has $2$ possible outcomes: Heads ($H$) or Tails ($T$). The total number of outcomes is determined by the Fundamental Counting Principle: $2 \times 2 \times 2 = 8$.
The sample space $S$ is defined as:
$S = \{HHH, HHT, HTH, THH, HTT, THT, TTH, TTT\}$
Two events $A$ and $B$ are defined as mutually exclusive if they cannot occur simultaneously. Formally, $A \cap B = \emptyset$, where $\emptyset$ is the null (empty) set. [By the Axiomatic Definition of Probability].
To satisfy the condition of mutual exclusivity, we must identify two subsets of $S$ that share no common elements.
To verify that $A$ and $B$ are mutually exclusive, we calculate their intersection:
$A \cap B = \{HHH\} \cap \{TTT\} = \emptyset$
[By the Principle of Disjoint Sets, since no outcome exists in both sets, the probability $P(A \cap B) = 0$.]
Since the set of outcomes where three heads appear and the set of outcomes where three tails appear have no intersection, they are mutually exclusive.
Final Solution: Event $A = \{HHH\}$ (getting three heads) and Event $B = \{TTT\}$ (getting three tails) are mutually exclusive.
Solution:
When a standard six-faced die is rolled, the set of all possible outcomes, denoted as the sample space $S$, is defined as:
$S = \{1, 2, 3, 4, 5, 6\}$
[By the definition of a discrete sample space for a fair die]
Event $E$ is defined as the event where the die shows a 4. Thus:
$E = \{4\}$
Event $F$ is defined as the event where the die shows an even number. The even numbers in the sample space $S$ are 2, 4, and 6. Thus:
$F = \{2, 4, 6\}$
To determine if two events are mutually exclusive, we must calculate the intersection of the two sets. Two events are mutually exclusive if and only if $E \cap F = \emptyset$, meaning the events share no common outcomes.
$E \cap F = \{4\} \cap \{2, 4, 6\}$
$E \cap F = \{4\}$
[Per the set-theoretic definition of intersection]
Since $E \cap F = \{4\}$, and $\{4\} \neq \emptyset$ (the intersection is not the empty set), there is an outcome common to both events.
Because the die showing "4" satisfies both the condition of being a "4" and the condition of being an "even number," the events are not mutually exclusive.
Final Solution: No, E and F are not mutually exclusive because E $\cap$ F = {4} $\neq$ $\emptyset$.
Solution:
When tossing three unbiased coins simultaneously, each coin has two possible outcomes: Heads ($H$) or Tails ($T$). The total number of elementary outcomes in the sample space $S$ is calculated as $2^n$, where $n=3$.
$S = \{HHH, HHT, HTH, THH, HTT, THT, TTH, TTT\}$
The total number of outcomes $|S| = 8$.
We define three events based on the number of heads appearing in the toss:
To confirm mutual exclusivity, we check the intersection of all pairs:
[By the definition of intersection of disjoint sets, the events are mutually exclusive].
To confirm the events are exhaustive, we take the union of $A, B, \text{ and } C$:
$A \cup B \cup C = \{TTT\} \cup \{HTT, THT, TTH\} \cup \{HHH, HHT, HTH, THH\}$
$A \cup B \cup C = \{TTT, HTT, THT, TTH, HHH, HHT, HTH, THH\} = S$
[Since the union of the events spans all possible outcomes in $S$, the collection is exhaustive].
Final Solution: The three events $A = \{TTT\}$, $B = \{HTT, THT, TTH\}$, and $C = \{HHH, HHT, HTH, THH\}$ are mutually exclusive and exhaustive.
Solution:
When three coins are tossed, each coin has two possible outcomes: Head ($H$) or Tail ($T$). Since there are three coins, the total number of elementary outcomes is given by $2^n$ where $n=3$.
The sample space $S$ is defined as:
$S = \{HHH, HHT, HTH, THH, HTT, THT, TTH, TTT\}$
Total number of outcomes, $n(S) = 8$.
Two events $A$ and $B$ are defined as not mutually exclusive if they have at least one common outcome, i.e., $A \cap B \neq \emptyset$ [Per the definition of Mutually Exclusive Events in Probability Theory].
Let us define the following two events:
Set A (At least two heads):
$A = \{HHH, HHT, HTH, THH\}$
Set B (At least two tails):
$B = \{HTT, THT, TTH, TTT\}$
To verify if these events are not mutually exclusive, we evaluate the intersection $A \cap B$.
By observing the sets $A$ and $B$:
$A \cap B = \emptyset$ (These specific sets are mutually exclusive).
Revision: To satisfy the requirement of "not mutually exclusive," we must redefine the events to ensure a non-empty intersection.
Let us define new events:
Set C: $\{HHT, HTH, THH\}$
Set D: $\{HHH, HHT, HTH, HTT\}$
Checking the intersection of $C$ and $D$:
$C \cap D = \{HHT, HTH\}$
Since $C \cap D \neq \emptyset$, the events share common outcomes ($HHT$ and $HTH$).
Final Solution: Two events that are not mutually exclusive are: Event C (getting exactly two heads) and Event D (getting a head on the first coin), because $C \cap D = \{HHT, HTH\}$, which is not an empty set.
Solution:
For a standard six-faced fair die, the possible outcomes of a single throw are represented by the set of integers from 1 to 6. This represents the total sample space ($S$).
$S = \{1, 2, 3, 4, 5, 6\}$
[Definition: The sample space is the set of all possible outcomes of a random experiment.]
The problem defines event $B$ as the occurrence of "a number greater than 7". We represent this as a subset of the sample space $S$ such that every element $x \in B$ satisfies $x > 7$.
Mathematically, we look for $B = \{x \in S : x > 7\}$.
Testing each element of $S$ against the condition $x > 7$:
[Logical Deduction: Since no element in the defined sample space $S$ satisfies the condition, the set $B$ contains no elements.]
An event that contains no outcomes from the sample space is termed an Impossible Event or the Null Event, denoted by the symbol $\phi$ or $\{\}$.
Final Solution: The event B is an impossible event, represented as $B = \phi$.
Solution:
When three unbiased coins are tossed simultaneously, each coin has $2$ possible outcomes ($H$ for Heads, $T$ for Tails). By the Fundamental Counting Principle, the total number of outcomes is $2^3 = 8$.
The sample space $S$ is defined as: $S = \{HHH, HHT, HTH, THH, HTT, THT, TTH, TTT\}$
Let us define Event $A$ and Event $B$ as follows:
| Operation | Result | Conclusion |
|---|---|---|
| $A \cap B$ | $\{HHH\} \cap \{TTT\} = \emptyset$ | Mutually Exclusive [By definition of disjoint sets] |
| $A \cup B$ | $\{HHH, TTT\}$ | $A \cup B \neq S$ because elements like $\{HHT, HTH...\}$ are missing. |
Final Solution: Event $A = \{HHH\}$ (getting exactly three heads) and Event $B = \{TTT\}$ (getting exactly three tails) are mutually exclusive because $A \cap B = \emptyset$, and they are not exhaustive because $A \cup B \neq S$.
Solution:
When rolling a pair of fair six-sided dice, each die has $6$ possible outcomes. The total number of outcomes in the sample space is $6 \times 6 = 36$. We define the sample space $S$ as the set of all ordered pairs $(x, y)$, where $x$ and $y \in \{1, 2, 3, 4, 5, 6\}$.
Event A: The sum of the numbers is greater than 8.
The possible sums are $\{9, 10, 11, 12\}$.
Event B: 2 occurs on either die.
This includes cases where 2 is on the first die, the second die, or both.
$B = \{(2,1), (2,2), (2,3), (2,4), (2,5), (2,6), (1,2), (3,2), (4,2), (5,2), (6,2)\}$
Event C: The sum is at least 7 and a multiple of 3.
Possible sums $\ge 7$ are $\{7, 8, 9, 10, 11, 12\}$. Multiples of 3 in this set are $\{9, 12\}$.
Two events $X$ and $Y$ are mutually exclusive if $X \cap Y = \emptyset$ [Definition of Mutually Exclusive Events].
| Pair | Intersection ($X \cap Y$) | Result |
|---|---|---|
| A and B | $\emptyset$ | Mutually Exclusive |
| A and C | $\{(3,6), (4,5), (5,4), (6,3), (6,6)\}$ | Not Mutually Exclusive |
| B and C | $\emptyset$ | Mutually Exclusive |
Final Solution: The pairs of events that are mutually exclusive are (A, B) and (B, C), because their intersections contain no common elements, whereas (A, C) is not mutually exclusive as $A \cap C = C$.
Solution:
When two dice are thrown simultaneously, each die has 6 faces $\{1, 2, 3, 4, 5, 6\}$. The sample space $S$ consists of all ordered pairs $(x, y)$, where $x$ is the outcome of the first die and $y$ is the outcome of the second die. The total number of outcomes is $n(S) = 6 \times 6 = 36$.
Event $A$ is defined as "getting an even number on the first die." The possible outcomes for $x$ are $\{2, 4, 6\}$. The outcomes for $y$ can be any integer from $1$ to $6$. $A = \{(2,1), (2,2), (2,3), (2,4), (2,5), (2,6), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)\}$. [Cardinality: $n(A) = 3 \times 6 = 18$].
Event $B$ is defined as "getting an odd number on the first die." The possible outcomes for $x$ are $\{1, 3, 5\}$. The outcomes for $y$ can be any integer from $1$ to $6$. $B = \{(1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6)\}$. [Cardinality: $n(B) = 3 \times 6 = 18$].
The complement event $B'$ consists of all outcomes in the sample space $S$ that are not in event $B$. By definition, $B' = S - B$. Since $S$ is the set of all pairs $(x, y)$ where $x \in \{1, 2, 3, 4, 5, 6\}$, and $B$ contains all pairs where $x \in \{1, 3, 5\}$, then $B'$ must contain all pairs where $x \in \{2, 4, 6\}$.
As derived in Step 3, the outcomes belonging to $B'$ are exactly the pairs where the first die shows an even number ($x \in \{2, 4, 6\}$). Comparing the set $A$ (defined in Step 2) and the set $B'$ (derived in Step 3): $A = \{(x, y) \mid x \in \{2, 4, 6\}, y \in \{1, \dots, 6\}\}$ $B' = \{(x, y) \mid x \in \{2, 4, 6\}, y \in \{1, \dots, 6\}\}$
Since $A = B'$, the statement is logically valid. [By the Law of Complementation in Set Theory, since the sample space is partitioned into $A$ (even first) and $B$ (odd first), $B^c$ is the set of all outcomes not in $B$, which is $A$.]
Final Solution: True. The event $A$ (getting an even number on the first die) is identical to the complement of event $B$ (getting an odd number on the first die) because the first die can only result in either an even or an odd number, and these events are mutually exclusive and collectively exhaustive.
Solution:
When two six-sided dice are thrown, each die has 6 outcomes ($1, 2, 3, 4, 5, 6$). The total number of outcomes in the sample space $S$ is $6 \times 6 = 36$.
$S = \{ (x, y) : x, y \in \{1, 2, 3, 4, 5, 6\} \}$
The event "A and B" denotes the intersection of set $A$ and set $B$ ($A \cap B$). This event consists of outcomes that belong to both Event A and Event B simultaneously [Per the Definition of Intersection in Set Theory].
An outcome $(x, y)$ belongs to $A \cap B$ if $x$ is simultaneously even and odd.
Since the set of even numbers $\{2, 4, 6\}$ and the set of odd numbers $\{1, 3, 5\}$ are mutually exclusive, there exists no element $x$ such that $x \in \{2, 4, 6\} \cap \{1, 3, 5\}$.
Therefore, $A \cap B = \emptyset$ [By the Property of Mutually Exclusive Events].
Since the intersection results in an empty set, the event "A and B" is an impossible event. There are no outcomes in the sample space where the first die is both even and odd.
Final Solution: $A \cap B = \phi$ (The event is impossible).
Solution:
When two six-sided dice are thrown, the sample space $S$ consists of all ordered pairs $(x, y)$, where $x, y \in \{1, 2, 3, 4, 5, 6\}$. The total number of outcomes is $n(S) = 6 \times 6 = 36$.
Event A (Even number on the first die): The first die can be $2, 4,$ or $6$. $A = \{(2,1), (2,2), (2,3), (2,4), (2,5), (2,6), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)\}$ $n(A) = 3 \times 6 = 18$.
Event B (Odd number on the first die): The first die can be $1, 3,$ or $5$. $B = \{(1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6)\}$ $n(B) = 3 \times 6 = 18$.
Two events are mutually exclusive if $A \cap B = \phi$ [Definition of Mutually Exclusive Events]. Evaluating the intersection: $A \cap B = \{(x, y) \in S : x \text{ is even and } x \text{ is odd}\}$ Since no integer can be simultaneously even and odd, $A \cap B = \phi$. Conclusion: A and B are mutually exclusive.
Two events are exhaustive if $A \cup B = S$ [Definition of Exhaustive Events]. $A \cup B$ contains all outcomes where the first die is either even or odd. Since every possible result on a die must be either even or odd, $A \cup B$ covers all $36$ outcomes in $S$. $n(A \cup B) = n(A) + n(B) = 18 + 18 = 36$. Since $n(A \cup B) = n(S)$, the union forms the complete sample space.
| Criteria | Mathematical Condition | Status |
|---|---|---|
| Mutually Exclusive | $A \cap B = \phi$ | True |
| Exhaustive | $A \cup B = S$ | True |
Final Solution: The statement is True. Events A and B are mutually exclusive because their intersection is an empty set (it is impossible for a number to be both even and odd simultaneously), and they are exhaustive because their union constitutes the entire sample space S.
Solution:
When three unbiased coins are tossed simultaneously, each coin has 2 possible outcomes ($H$ or $T$). By the Fundamental Counting Principle, the total number of outcomes is $2^3 = 8$. The sample space $S$ is defined as:
$S = \{HHH, HHT, HTH, THH, HTT, THT, TTH, TTT\}$
We define the sets based on the criteria provided:
[Per the axioms of Probability Theory], an event is classified as a simple event (or elementary event) if and only if it consists of exactly one outcome of the sample space $S$. Mathematically, an event $E$ is simple if $|E| = 1$.
| Event | Sample Points | Cardinality ($|E|$) | Classification |
|---|---|---|---|
| A | $\{HHH\}$ | 1 | Simple |
| B | $\{HHT, HTH, THH\}$ | 3 | Compound |
| C | $\{TTT\}$ | 1 | Simple |
| D | $\{HHH, HHT, HTH, HTT\}$ | 4 | Compound |
Since events A and C contain exactly one elementary outcome from the sample space, they satisfy the definition of a simple event.
Final Solution: The simple events are A and C.
Solution:
When three coins are tossed, each coin has 2 possible outcomes: Head ($H$) or Tail ($T$). The total number of outcomes is $2^3 = 8$. The sample space $S$ is defined as:
$S = \{HHH, HHT, HTH, THH, HTT, THT, TTH, TTT\}$
Based on the conditions provided, we define the subsets of $S$ for events $A, B, C,$ and $D$:
Two events $E_1$ and $E_2$ are mutually exclusive if and only if $E_1 \cap E_2 = \emptyset$ [Per the definition of disjoint sets in Probability Theory].
| Pair | Intersection | Result |
|---|---|---|
| $A \cap B$ | $\emptyset$ | Mutually Exclusive |
| $A \cap C$ | $\emptyset$ | Mutually Exclusive |
| $A \cap D$ | $\{HHH\}$ | Not Mutually Exclusive |
| $B \cap C$ | $\emptyset$ | Mutually Exclusive |
| $B \cap D$ | $\{HHT, HTH\}$ | Not Mutually Exclusive |
| $C \cap D$ | $\emptyset$ | Mutually Exclusive |
Final Solution: The pairs of events that are mutually exclusive are (A, B), (A, C), (B, C), and (C, D).
Solution:
When two six-sided dice are thrown, each die has an outcome set of $\{1, 2, 3, 4, 5, 6\}$. The sample space $S$ consists of all ordered pairs $(x, y)$, where $x$ is the outcome of the first die and $y$ is the outcome of the second die. The total number of outcomes is $6 \times 6 = 36$ [By the Fundamental Counting Principle].
Event $A$ (Even number on the first die): $A = \{(2,1), (2,2), (2,3), (2,4), (2,5), (2,6), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)\}$
Event $C$ (Sum of numbers $\le 5$): The possible sums are 2, 3, 4, and 5. $C = \{(1,1), (1,2), (1,3), (1,4), (2,1), (2,2), (2,3), (3,1), (3,2), (4,1)\}$
The event "A but not C" is represented in set theory as $A \setminus C$ or $A \cap C^c$. This requires identifying elements present in $A$ that are not present in $C$.
Elements of $A$ that are also in $C$: Intersection $A \cap C = \{(2,1), (2,2), (2,3), (4,1)\}$.
To find $A \setminus C$, we remove these elements from set $A$:
| Outcome Type | Resulting Set Elements |
|---|---|
| First die = 2 | $\{(2,4), (2,5), (2,6)\}$ |
| First die = 4 | $\{(4,2), (4,3), (4,4), (4,5), (4,6)\}$ |
| First die = 6 | $\{(6,1), (6,2), (6,3), (6,4), (6,5), (6,6)\}$ |
The set $A \setminus C$ contains all outcomes where the first die is even and the sum of the dice is strictly greater than 5.
$A \setminus C = \{(2,4), (2,5), (2,6), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)\}$
Final Solution: The event "A but not C" is the set of 14 outcomes: {(2,4), (2,5), (2,6), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)}
Solution:
When two six-faced dice are thrown, the sample space $S$ consists of all ordered pairs $(x, y)$, where $x$ is the result of the first die and $y$ is the result of the second die. The total number of outcomes is $6 \times 6 = 36$.
$S = \{ (1,1), (1,2), \dots, (6,6) \}$
Event A: Getting an even number on the first die.
Event B: Getting an odd number on the first die.
Two events are defined as mutually exclusive if and only if their intersection is the empty set, denoted as $A \cap B = \emptyset$. [Per the Set Theoretic Definition of Probability].
Analyzing $A \cap B$:
Set A contains pairs where the first element $x \in \{2, 4, 6\}$.
Set B contains pairs where the first element $x \in \{1, 3, 5\}$.
Since the set of even integers $\{2, 4, 6\}$ and odd integers $\{1, 3, 5\}$ have no common elements, $A \cap B = \emptyset$.
Because the first die cannot be both even and odd simultaneously, the events $A$ and $B$ cannot occur at the same time. Therefore, $A \cap B = \emptyset$.
Final Solution: True. The events A and B are mutually exclusive because it is impossible for the first die to show an even number and an odd number simultaneously, resulting in an empty intersection ($A \cap B = \emptyset$).
Solution:
The sample space $S$ for two thrown dice consists of $6 \times 6 = 36$ ordered pairs $(x, y)$, where $x, y \in \{1, 2, 3, 4, 5, 6\}$.
We define the events as follows:
Per the Complement Rule in set theory, $E'$ contains all elements of $S$ not present in $E$ [By Set Complement Axiom].
We seek the intersection $A \cap B' \cap C'$.
1. Since $B' = A$, the expression simplifies to $A \cap A \cap C'$, which is equivalent to $A \cap C'$.
2. We need to identify outcomes in $A$ (first die is even) that are not in $C$ (sum > 5).
| Event A Outcomes (x is even) | Sum | Is Sum $\le 5$? (In C) | Included in $A \cap C'$? |
|---|---|---|---|
| (2,1), (2,2), (2,3) | 3, 4, 5 | Yes | No |
| (2,4), (2,5), (2,6) | 6, 7, 8 | No | Yes |
| (4,1) | 5 | Yes | No |
| (4,2), (4,3), (4,4), (4,5), (4,6) | 6, 7, 8, 9, 10 | No | Yes |
| (6,1), (6,2), (6,3), (6,4), (6,5), (6,6) | 7, 8, 9, 10, 11, 12 | No | Yes |
The set $A \cap B' \cap C'$ is the set of all outcomes $(x, y)$ where $x \in \{2, 4, 6\}$ and $x + y > 5$.
The resulting set is:
$\{ (2,4), (2,5), (2,6), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6) \}$
Final Solution: $A \cap B' \cap C' = \{ (2,4), (2,5), (2,6), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6) \}$
Solution:
When two six-sided dice are thrown, each die has an outcome set of $\{1, 2, 3, 4, 5, 6\}$. The total sample space $S$ consists of $6 \times 6 = 36$ ordered pairs $(d_1, d_2)$, where $d_1$ is the result of the first die and $d_2$ is the result of the second die.
$S = \{(1,1), (1,2), \dots, (6,6)\}$ [By the Fundamental Counting Principle].
Event $B$ is defined as "getting an odd number on the first die." Thus, $d_1 \in \{1, 3, 5\}$.
$B = \{(1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6)\}$
Event $C$ is defined as "getting the sum of the numbers on the dice $\le 5$."
$C = \{(1,1), (1,2), (1,3), (1,4), (2,1), (2,2), (2,3), (3,1), (3,2), (4,1)\}$
The event "B or C" is represented by the union $B \cup C$. This set includes all outcomes that are in $B$, or in $C$, or in both [Set Theory Definition of Union].
| Elements exclusively in $B$ | Elements in $B \cap C$ | Elements exclusively in $C$ |
|---|---|---|
| (1,5), (1,6), (3,3), (3,4), (3,5), (3,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6) | (1,1), (1,2), (1,3), (1,4), (3,1), (3,2) | (2,1), (2,2), (2,3), (4,1) |
Combining the sets and removing duplicates:
$B \cup C = \{(1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (2,1), (2,2), (2,3), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (4,1), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6)\}$
Final Solution: The set $B \cup C = \{(1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (2,1), (2,2), (2,3), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (4,1), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6)\}$
Solution:
When three coins are tossed simultaneously, each coin has two possible outcomes: Head ($H$) or Tail ($T$). The total number of outcomes is $2^n$, where $n=3$. Thus, $2^3 = 8$ outcomes.
The sample space $S$ is defined as:
$S = \{HHH, HHT, HTH, THH, HTT, THT, TTH, TTT\}$
Based on the problem statement, we define the sets for each event:
[Per the definition of Probability Theory]: An event is termed a Compound Event if it consists of more than one sample point from the sample space $S$. Conversely, an event consisting of exactly one sample point is a Simple (or Elementary) Event.
| Event | Sample Points | Count ($n$) | Classification |
|---|---|---|---|
| A | $\{HHH\}$ | 1 | Simple Event |
| B | $\{HHT, HTH, THH\}$ | 3 | Compound Event |
| C | $\{TTT\}$ | 1 | Simple Event |
| D | $\{HHH, HHT, HTH, HTT\}$ | 4 | Compound Event |
An event is compound if the cardinality of its set is greater than 1 ($|E| > 1$). Observing the analysis in Step 4, Events B and D contain multiple outcomes, satisfying the criteria for compound events.
Final Solution: The events B and D are Compound Events because they consist of more than one sample point from the sample space.
Solution:
When two six-faced dice are thrown, the sample space $S$ consists of all possible ordered pairs $(x, y)$, where $x$ is the result of the first die and $y$ is the result of the second die. $x, y \in \{1, 2, 3, 4, 5, 6\}$.
The total number of outcomes is $n(S) = 6 \times 6 = 36$.
Event $B$ is defined as "getting an odd number on the first die":
$B = \{ (1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6) \}$
Event $C$ is defined as "getting the sum of the numbers on the dice $\le 5$":
$C = \{ (1,1), (1,2), (1,3), (1,4), (2,1), (2,2), (2,3), (3,1), (3,2), (4,1) \}$
The notation $B \cap C$ refers to the intersection of events, which constitutes outcomes that belong to both set $B$ and set $C$ [Per the Set Theory Definition of Intersection].
| Outcome | Sum ($x+y$) | Odd First Die? | $\le 5$? |
|---|---|---|---|
| (1,1) | 2 | Yes | Yes |
| (1,2) | 3 | Yes | Yes |
| (1,3) | 4 | Yes | Yes |
| (1,4) | 5 | Yes | Yes |
| (3,1) | 4 | Yes | Yes |
| (3,2) | 5 | Yes | Yes |
Final Solution: The intersection of events B and C is $B \cap C = \{ (1,1), (1,2), (1,3), (1,4), (3,1), (3,2) \}$.