Math Problem Statement

Consider the Venn diagram shown below. Determine the following cardinalities: n(A'), n(A ∪ B), n(A ∩ C), n(A ∩ B ∩ C), n(A' ∪ B ∪ C).

Solution

Let's work through the Venn diagram and answer the questions. The sets AA, BB, and CC are represented by circles with different numbers inside each region, corresponding to specific intersections and unions of the sets.

The values in the Venn diagram:

  • Region AA only: 4
  • Region BB only: 5
  • Region CC only: 7
  • ABA \cap B (excluding CC): 6
  • ACA \cap C (excluding BB): 1
  • BCB \cap C (excluding AA): 10
  • ABCA \cap B \cap C: 8
  • Outside ABCA \cup B \cup C: 12

Now, let's determine the following cardinalities:

  1. n(Aˉ)n(\bar{A}) (the number of elements outside AA):

    • Everything outside AA includes the values from regions not part of AA, which are: 5(B only)+10(BC)+7(C only)+12(outside all sets)=345 \, (B \text{ only}) + 10 \, (B \cap C) + 7 \, (C \text{ only}) + 12 \, (\text{outside all sets}) = 34 Therefore, n(Aˉ)=34n(\bar{A}) = 34.
  2. n(AB)n(A \cup B) (the union of sets AA and BB):

    • Add all the regions that are part of AA, BB, or both: 4(A only)+6(AB)+8(ABC)+5(B only)+1(AC)=244 \, (A \text{ only}) + 6 \, (A \cap B) + 8 \, (A \cap B \cap C) + 5 \, (B \text{ only}) + 1 \, (A \cap C) = 24 Therefore, n(AB)=24n(A \cup B) = 24.
  3. n(AC)n(A \cap C) (the intersection of sets AA and CC):

    • Add the regions that are part of both AA and CC: 1(AC only)+8(ABC)=91 \, (A \cap C \text{ only}) + 8 \, (A \cap B \cap C) = 9 Therefore, n(AC)=9n(A \cap C) = 9.
  4. n(ABC)n(A \cap B \cap C) (the intersection of AA, BB, and CC):

    • This region is given as 88. Therefore, n(ABC)=8n(A \cap B \cap C) = 8.
  5. n(AˉBC)n(\bar{A} \cup B \cup C) (the union of everything outside AA, and the sets BB and CC):

    • This would be everything in BB, CC, or outside AA: 5(B only)+10(BC)+7(C only)+12(outside all sets)=345 \, (B \text{ only}) + 10 \, (B \cap C) + 7 \, (C \text{ only}) + 12 \, (\text{outside all sets}) = 34 Therefore, n(AˉBC)=34n(\bar{A} \cup B \cup C) = 34.

Summary:

  1. n(Aˉ)=34n(\bar{A}) = 34
  2. n(AB)=24n(A \cup B) = 24
  3. n(AC)=9n(A \cap C) = 9
  4. n(ABC)=8n(A \cap B \cap C) = 8
  5. n(AˉBC)=34n(\bar{A} \cup B \cup C) = 34

Would you like further details or explanations? Here are some follow-up questions to consider:

  1. How would the calculation change if an additional region was added to the Venn diagram?
  2. Can we find n(AB)n(A \cap B) from this diagram?
  3. How would n(Bˉ)n(\bar{B}) be calculated from the Venn diagram?
  4. Can you determine the total number of elements in the universal set?
  5. What is the formula for the union of three sets, and how would it apply here?

Tip: When calculating the union of two sets, remember to subtract any intersections that were counted twice.

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Math Problem Analysis

Mathematical Concepts

Set Theory
Venn Diagrams
Cardinality

Formulas

n(A ∪ B) = n(A) + n(B) - n(A ∩ B)
n(A ∩ C) = n(A ∩ C)
n(A ∩ B ∩ C) = n(A ∩ B ∩ C)
n(A' ∪ B ∪ C) = Total - n(A ∪ B ∪ C)
n(A') = Total - n(A)

Theorems

Inclusion-Exclusion Principle

Suitable Grade Level

Grades 11-12