Math Problem Statement

Let the Universal Set, S, have 93 elements. A and B are subsets of S. Set A contains 26 elements and Set B contains 19 elements. If the total number of elements in either A or B is 44, how many elements are in B but not in A?

Solution

The problem you've shared involves set theory and can be solved using the principle of inclusion and exclusion. Let's break it down:

Information provided:

  • S=93|S| = 93 (The universal set has 93 elements)
  • A=26|A| = 26 (Set AA contains 26 elements)
  • B=19|B| = 19 (Set BB contains 19 elements)
  • AB=44|A \cup B| = 44 (The number of elements in AA or BB is 44)

The goal is to find how many elements are in BB but not in AA, which is represented by BA|B \setminus A|.

Step-by-step solution:

  1. The total number of elements in either AA or BB is given by the union formula: AB=A+BAB|A \cup B| = |A| + |B| - |A \cap B| Plugging in the known values: 44=26+19AB44 = 26 + 19 - |A \cap B| Simplifying: 44=45AB44 = 45 - |A \cap B| Therefore, the number of elements common to both AA and BB (i.e., AB|A \cap B|) is: AB=4544=1|A \cap B| = 45 - 44 = 1

  2. Now, to find how many elements are in BB but not in AA (i.e., BA|B \setminus A|), we subtract the number of elements in ABA \cap B from the total number of elements in BB: BA=BAB=191=18|B \setminus A| = |B| - |A \cap B| = 19 - 1 = 18

Final Answer:

There are 18 elements in BB but not in AA.

Would you like further clarification or details on this?

Here are five related questions to explore:

  1. How many elements are in ABA \cap B?
  2. What is the number of elements in ABA \setminus B?
  3. How many elements are in S(AB)S \setminus (A \cup B)?
  4. What would happen if AB|A \cup B| was different?
  5. How do we compute AB|A \cup B| for more than two sets?

Tip: The principle of inclusion and exclusion is powerful for solving problems involving multiple sets. It allows us to account for overlaps and avoid overcounting.

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Math Problem Analysis

Mathematical Concepts

Set Theory
Inclusion-Exclusion Principle

Formulas

|A ∪ B| = |A| + |B| - |A ∩ B|
|B \ A| = |B| - |A ∩ B|

Theorems

Inclusion-Exclusion Principle

Suitable Grade Level

Grades 9-12