1. Set [tex]\( A \)[/tex] is the set of factors of 24, set [tex]\( B \)[/tex] is the set of even natural numbers less than 25, and set [tex]\( C \)[/tex] is the set of even natural numbers less than 13. The universal set [tex]\( U \)[/tex] is the set of natural numbers less than 24. Use the sets given below to answer questions [tex]\( a-g \)[/tex].

[tex]\[
\begin{array}{r}
A = \{1, 2, 3, 4, 6, 8, 12, 24\} \\
B = \{2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24\} \\
C = \{2, 4, 6, 8, 10, 12\} \\
U = \{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24\}
\end{array}
\][/tex]

a) Is [tex]\( C \subset B \)[/tex]? Explain why or why not.

b) What is [tex]\( A \cap B \)[/tex]?

c) What is [tex]\( A \cap C \)[/tex]?

d) What is [tex]\( A \cup B \)[/tex]?

e) What is [tex]\( A \cup C \)[/tex]?

f) What is [tex]\( A^c \)[/tex]?



Answer :

Certainly! Let's address each part of the problem one step at a time.

### a) Is [tex]\( C \subset B \)[/tex]? Explain why or why not.

To determine if [tex]\( C \)[/tex] is a subset of [tex]\( B \)[/tex], we need to check whether every element in [tex]\( C \)[/tex] is also in [tex]\( B \)[/tex]. The sets are as follows:
- [tex]\( C = \{2, 4, 6, 8, 10, 12\} \)[/tex]
- [tex]\( B = \{2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24\} \)[/tex]

Each element in [tex]\( C \)[/tex] is present in [tex]\( B \)[/tex]. Therefore, [tex]\( C \)[/tex] is a subset of [tex]\( B \)[/tex]:
[tex]\[ C \subseteq B \][/tex]

### c) What is [tex]\( A \cap B \)[/tex]?

The intersection of sets [tex]\( A \)[/tex] and [tex]\( B \)[/tex], denoted [tex]\( A \cap B \)[/tex], includes all elements that are present in both sets.

- [tex]\( A = \{1, 2, 3, 4, 6, 8, 12, 24\} \)[/tex]
- [tex]\( B = \{2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24\} \)[/tex]

The common elements are [tex]\( \{2, 4, 6, 8, 12, 24\} \)[/tex]:
[tex]\[ A \cap B = \{2, 4, 6, 8, 12, 24\} \][/tex]

### d) What is [tex]\( A \cap C \)[/tex]?

The intersection of sets [tex]\( A \)[/tex] and [tex]\( C \)[/tex], denoted [tex]\( A \cap C \)[/tex], includes all elements that are present in both sets.

- [tex]\( A = \{1, 2, 3, 4, 6, 8, 12, 24\} \)[/tex]
- [tex]\( C = \{2, 4, 6, 8, 10, 12\} \)[/tex]

The common elements are [tex]\( \{2, 4, 6, 8, 12\} \)[/tex]:
[tex]\[ A \cap C = \{2, 4, 6, 8, 12\} \][/tex]

### e) What is [tex]\( A \cup B \)[/tex]?

The union of sets [tex]\( A \)[/tex] and [tex]\( B \)[/tex], denoted [tex]\( A \cup B \)[/tex], includes all elements that are present in either set or both sets.

- [tex]\( A = \{1, 2, 3, 4, 6, 8, 12, 24\} \)[/tex]
- [tex]\( B = \{2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24\} \)[/tex]

The combined set is:
[tex]\[ A \cup B = \{1, 2, 3, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24\} \][/tex]

### f) What is [tex]\( A \cup C \)[/tex]?

The union of sets [tex]\( A \)[/tex] and [tex]\( C \)[/tex], denoted [tex]\( A \cup C \)[/tex], includes all elements that are present in either set or both sets.

- [tex]\( A = \{1, 2, 3, 4, 6, 8, 12, 24\} \)[/tex]
- [tex]\( C = \{2, 4, 6, 8, 10, 12\} \)[/tex]

The combined set is:
[tex]\[ A \cup C = \{1, 2, 3, 4, 6, 8, 10, 12, 24\} \][/tex]

### g) What is [tex]\( A^c \)[/tex]?

The complement of set [tex]\( A \)[/tex] in the universal set [tex]\( U \)[/tex], denoted [tex]\( A^c \)[/tex], includes all elements in [tex]\( U \)[/tex] that are not in [tex]\( A \)[/tex].

- [tex]\( A = \{1, 2, 3, 4, 6, 8, 12, 24\} \)[/tex]
- [tex]\( U = \{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24\} \)[/tex]

The elements in [tex]\( U \)[/tex] but not in [tex]\( A \)[/tex] are:
[tex]\[ A^c = \{5, 7, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23\} \][/tex]

To summarize:

a) [tex]\( C \subseteq B \)[/tex] : True

c) [tex]\( A \cap B = \{2, 4, 6, 8, 12, 24\} \)[/tex]

d) [tex]\( A \cap C = \{2, 4, 6, 8, 12\} \)[/tex]

e) [tex]\( A \cup B = \{1, 2, 3, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24\} \)[/tex]

f) [tex]\( A \cup C = \{1, 2, 3, 4, 6, 8, 10, 12, 24\} \)[/tex]

g) [tex]\( A^c = \{5, 7, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23\} \)[/tex]