Math Problem Statement

A sample space contains 7 sample points and events A and B as seen in the Venn diagram. Let P(1) = P(2) = P(3) = P(7) = 0.1, P(4) = P(5) = 0.05, and P(6) = 0.5. Use the Venn diagram and the probabilities of the sample points to find P(A ∪ B), P(B^c), P(B), and P(A ∪ A^c).

Solution

Let's analyze the problem using the given data:

Given:

  • Sample space points: 7 points.
  • Probabilities of individual points:
    • P(1)=P(2)=P(3)=P(7)=0.1P(1) = P(2) = P(3) = P(7) = 0.1,
    • P(4)=P(5)=0.05P(4) = P(5) = 0.05,
    • P(6)=0.5P(6) = 0.5.
  • Events AA and BB represented by a Venn diagram.

From the Venn diagram:

  • A={1,2,3,5}A = \{1, 2, 3, 5\},
  • B={2,3,4,7}B = \{2, 3, 4, 7\}.

Now, solve each part:


(a) P(AB)P(A \cup B)

The union of AA and BB is: AB={1,2,3,4,5,7}.A \cup B = \{1, 2, 3, 4, 5, 7\}. The probability is: P(AB)=P(1)+P(2)+P(3)+P(4)+P(5)+P(7).P(A \cup B) = P(1) + P(2) + P(3) + P(4) + P(5) + P(7). Substituting: P(AB)=0.1+0.1+0.1+0.05+0.05+0.1=0.5.P(A \cup B) = 0.1 + 0.1 + 0.1 + 0.05 + 0.05 + 0.1 = 0.5.


(b) P(Bc)P(B^c)

The complement of BB is: Bc={1,5,6}.B^c = \{1, 5, 6\}. The probability is: P(Bc)=P(1)+P(5)+P(6).P(B^c) = P(1) + P(5) + P(6). Substituting: P(Bc)=0.1+0.05+0.5=0.65.P(B^c) = 0.1 + 0.05 + 0.5 = 0.65.


(c) P(B)P(B)

From the Venn diagram: B={2,3,4,7}.B = \{2, 3, 4, 7\}. The probability is: P(B)=P(2)+P(3)+P(4)+P(7).P(B) = P(2) + P(3) + P(4) + P(7). Substituting: P(B)=0.1+0.1+0.05+0.1=0.35.P(B) = 0.1 + 0.1 + 0.05 + 0.1 = 0.35.


(d) P(AAc)P(A \cup A^c)

The union of AA and its complement (AcA^c) is the entire sample space. Hence: P(AAc)=1.P(A \cup A^c) = 1.


Final Answers:

(a) P(AB)=0.5P(A \cup B) = 0.5,
(b) P(Bc)=0.65P(B^c) = 0.65,
(c) P(B)=0.35P(B) = 0.35,
(d) P(AAc)=1P(A \cup A^c) = 1.


Would you like a deeper explanation or any step clarified?


Here are 5 related questions for further understanding:

  1. What is the relationship between the union and intersection of two events?
  2. How can we compute P(AB)P(A \cap B) from the given data?
  3. How is the probability of BcB^c always related to P(B)P(B)?
  4. Can you explain why P(AAc)=1P(A \cup A^c) = 1 is always true?
  5. How does the sample space affect the calculation of probabilities?

Tip: Always double-check whether the events in a probability problem overlap to avoid double counting.

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Math Problem Analysis

Mathematical Concepts

Probability
Union and Intersection of Sets
Complement of a Set

Formulas

P(A ∪ B) = P(A) + P(B) - P(A ∩ B)
P(B^c) = 1 - P(B)
P(A ∪ A^c) = 1

Theorems

Addition Rule of Probability
Law of Complements

Suitable Grade Level

Grades 9-12