Discover a world of knowledge at Westonci.ca, where experts and enthusiasts come together to answer your questions. Discover comprehensive answers to your questions from knowledgeable professionals on our user-friendly platform. Join our Q&A platform to connect with experts dedicated to providing accurate answers to your questions in various fields.

4) [tex]\( A \)[/tex] and [tex]\( B \)[/tex] are two subsets of a universal set [tex]\( U \)[/tex] where [tex]\( n(U) = 210 \)[/tex], [tex]\( n(A) = 120 \)[/tex], [tex]\( n(B) = 60 \)[/tex], and [tex]\( n((A \cup B)') = 45 \)[/tex].

(a) Show it in a Venn diagram.

(b) Find the value of only [tex]\( A \)[/tex].

(c) Find the value of [tex]\( A \cap B \)[/tex].

Sagot :

Alright, let's approach this problem methodically. Given the information:

- [tex]\( n(U) = 210 \)[/tex]
- [tex]\( n(A) = 120 \)[/tex]
- [tex]\( n(B) = 60 \)[/tex]
- [tex]\( n((A \cup B)') = 45 \)[/tex]

We need to find:
- The Venn diagram representation.
- The value of only [tex]\( A \)[/tex].
- The value of [tex]\( A \cap B \)[/tex].

### Step-by-Step Solution:

#### (a) Venn Diagram Representation

1. Universal Set [tex]\( U \)[/tex]: This describes the entire set, which contains all elements we're considering. The total number of elements in [tex]\( U \)[/tex] is 210.

2. Subset [tex]\( A \)[/tex]: A subset of [tex]\( U \)[/tex] with 120 elements ( [tex]\( n(A) = 120 \)[/tex] ).

3. Subset [tex]\( B \)[/tex]: Another subset of [tex]\( U \)[/tex] with 60 elements ( [tex]\( n(B) = 60 \)[/tex] ).

4. Complement of [tex]\( A \cup B \)[/tex]: The number of elements not in [tex]\( A \cup B \)[/tex] is 45 ( [tex]\( n((A \cup B)') = 45 \)[/tex] ).

The point is to show the relationships and overlapping sections in the Venn diagram:
- Let the part of [tex]\( A \)[/tex] that does not intersect [tex]\( B \)[/tex] be [tex]\( A_{\text{only}} \)[/tex].
- Let the part of [tex]\( B \)[/tex] that does not intersect [tex]\( A \)[/tex] be [tex]\( B_{\text{only}} \)[/tex].
- Let the overlapping part (intersection of [tex]\( A \)[/tex] and [tex]\( B \)[/tex]) be represented as [tex]\( A \cap B \)[/tex].

#### (b) Finding the Value of Only [tex]\( A \)[/tex]

To find only [tex]\( A \)[/tex], we need to determine the value of [tex]\( A \)[/tex] excluding the part that intersects with [tex]\( B \)[/tex].

The values calculated:

1. Calculate [tex]\( n(A \cup B) \)[/tex]:
- Since [tex]\( n((A \cup B)') = 45 \)[/tex], the number of elements in [tex]\( A \cup B \)[/tex] can be found from:
[tex]\[ n(A \cup B) = n(U) - n((A \cup B)') \][/tex]
[tex]\[ n(A \cup B) = 210 - 45 \][/tex]
[tex]\[ n(A \cup B) = 165 \][/tex]

2. Calculate [tex]\( n(A \cap B) \)[/tex] using the principle of inclusion-exclusion:
[tex]\[ n(A \cup B) = n(A) + n(B) - n(A \cap B) \][/tex]
Solving for [tex]\( n(A \cap B) \)[/tex]:
[tex]\[ 165 = 120 + 60 - n(A \cap B) \][/tex]
[tex]\[ 165 = 180 - n(A \cap B) \][/tex]
[tex]\[ n(A \cap B) = 180 - 165 \][/tex]
[tex]\[ n(A \cap B) = 15 \][/tex]

3. Calculate the Value of Only [tex]\( A \)[/tex]:
[tex]\[ \text{Only } A = n(A) - n(A \cap B) \][/tex]
[tex]\[ \text{Only } A = 120 - 15 \][/tex]
[tex]\[ \text{Only } A = 105 \][/tex]

#### (c) Finding the Value of [tex]\( A \cap B \)[/tex]

From our calculations above, we found that:
[tex]\[ n(A \cap B) = 15 \][/tex]

### Conclusion:

- (a): The Venn diagram would depict the total universal set [tex]\( U \)[/tex], with two overlapping subsets [tex]\( A \)[/tex] and [tex]\( B \)[/tex]. [tex]\( A \cup B \)[/tex]'s complement contains 45 elements, meaning 165 elements fall within either [tex]\( A \)[/tex] or [tex]\( B \)[/tex] or their intersection.

- (b): The value of only [tex]\( A \)[/tex] is [tex]\( \boxed{105} \)[/tex].

- (c): The value of [tex]\( A \cap B \)[/tex] is [tex]\( \boxed{15} \)[/tex].

Thus, the calculations are neatly confirmed.
We appreciate your time. Please revisit us for more reliable answers to any questions you may have. We appreciate your time. Please revisit us for more reliable answers to any questions you may have. We're glad you chose Westonci.ca. Revisit us for updated answers from our knowledgeable team.