Math Problem Statement

Consider the Venn diagram shown below. Determine the following cardinalities: (a) n(A^c) = 22, (b) n(A ∪ B) = ?, (c) n(A ∩ C^c) = ?, (d) n(A ∩ B ∩ C) = ?, (e) n(A ∪ B ∪ C) = ?, (f) n(A^c ∩ B ∩ C) = ?

Solution

Let's analyze the Venn diagram and the set notations in the image you provided. We will calculate the cardinalities step by step.

Venn Diagram Breakdown:

The Venn diagram consists of three sets AA, BB, and CC. Here are the values for each region:

  • Only AA: 11
  • Only BB: 7
  • Only CC: 9
  • ABA \cap B: 2
  • ACA \cap C: 6
  • BCB \cap C: 5
  • ABCA \cap B \cap C: 3

Now, let's solve the questions:

(a) n(Ac)=22n(A^c) = 22

This value is already provided. It represents the number of elements outside of set AA.

(b) n(AB)n(A \cup B)

To calculate the union of sets AA and BB, we sum all the values in regions where AA, BB, or both sets are present. That includes:

  • Only AA: 11
  • Only BB: 7
  • ABA \cap B: 2
  • ACBA \cap C \cap B: 3 (since it's part of both AA and BB)

So: n(AB)=11+7+2+3=23n(A \cup B) = 11 + 7 + 2 + 3 = 23

(c) n(ACc)n(A \cap C^c)

The complement of CC is all the regions outside of CC. So, we consider elements in AA that do not intersect with CC, which includes:

  • Only AA: 11
  • ABA \cap B: 2

So: n(ACc)=11+2=13n(A \cap C^c) = 11 + 2 = 13

(d) n(ABC)n(A \cap B \cap C)

This is given directly by the diagram: n(ABC)=3n(A \cap B \cap C) = 3

(e) n(ABC)n(A \cup B \cup C)

For the union of all three sets AA, BB, and CC, we sum all regions in the Venn diagram:

  • Only AA: 11
  • Only BB: 7
  • Only CC: 9
  • ABA \cap B: 2
  • ACA \cap C: 6
  • BCB \cap C: 5
  • ABCA \cap B \cap C: 3

So: n(ABC)=11+7+9+2+6+5+3=43n(A \cup B \cup C) = 11 + 7 + 9 + 2 + 6 + 5 + 3 = 43

(f) n(AcBC)n(A^c \cap B \cap C)

This refers to the elements that are outside of AA but within both BB and CC. Looking at the Venn diagram, the only region that fits this is the intersection of BCB \cap C that does not include AA, which is:

  • BCB \cap C: 5

So: n(AcBC)=5n(A^c \cap B \cap C) = 5

Final answers:

  • (a) n(Ac)=22n(A^c) = 22 (given)
  • (b) n(AB)=23n(A \cup B) = 23
  • (c) n(ACc)=13n(A \cap C^c) = 13
  • (d) n(ABC)=3n(A \cap B \cap C) = 3
  • (e) n(ABC)=43n(A \cup B \cup C) = 43
  • (f) n(AcBC)=5n(A^c \cap B \cap C) = 5

Do you want more details on any of these?

Here are 5 related questions to consider:

  1. How would the cardinalities change if an extra element were added to set ABCA \cap B \cap C?
  2. Can you compute n(Bc)n(B^c) from the Venn diagram?
  3. What is n(Cc)n(C^c), and how does it relate to the other complements?
  4. How would you calculate n(ABcC)n(A \cap B^c \cap C)?
  5. What is the significance of union and intersection in probability theory?

Tip: When analyzing Venn diagrams, carefully identify and sum the distinct regions for each operation (union, intersection, complement). This avoids double-counting elements.

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Math Problem Analysis

Mathematical Concepts

Set Theory
Venn Diagrams
Union and Intersection
Set Complements

Formulas

Union: A ∪ B includes all elements in either A or B or both.
Intersection: A ∩ B includes all elements common to both A and B.
Complement: A^c includes all elements not in A.

Theorems

Principle of Inclusion and Exclusion

Suitable Grade Level

Grades 9-12