Question

Given sets [tex] P, Q, [/tex] and [tex] S [/tex] above, which of the following sets represents [tex] S \cap (P \cup Q) [/tex] (the intersection of [tex] S [/tex] with the union of sets [tex] P [/tex] and [tex] Q [/tex])?

[tex]\[
\begin{array}{l}
P=\{6,7,11,12,15\} \\
Q=\{4,7,12,15,20\} \\
S=\{3,4,11,12,16\}
\end{array}
\][/tex]

A. [tex] \{3,4,7,11,12,15,16\} [/tex]
B. [tex] \{4,6,7,11,12,15,20\} [/tex]
C. [tex] \{4,7,12,15\} [/tex]
D. [tex] \{4,11,12\} [/tex]



Answer :

To find the intersection of [tex]\( S \)[/tex] with the union of sets [tex]\( P \)[/tex] and [tex]\( Q \)[/tex], we need to perform the following steps:

1. Calculate the union of sets [tex]\( P \)[/tex] and [tex]\( Q \)[/tex]:
The union [tex]\( P \cup Q \)[/tex] is the set containing all unique elements from both [tex]\( P \)[/tex] and [tex]\( Q \)[/tex].

Given:
[tex]\[ P = \{6, 7, 11, 12, 15\} \][/tex]
[tex]\[ Q = \{4, 7, 12, 15, 20\} \][/tex]

The union [tex]\( P \cup Q \)[/tex] is:
[tex]\[ \{4, 6, 7, 11, 12, 15, 20\} \][/tex]

2. Calculate the intersection of set [tex]\( S \)[/tex] with the union [tex]\( P \cup Q \)[/tex]:
The intersection [tex]\( S \cap (P \cup Q) \)[/tex] is the set of elements that are common to both [tex]\( S \)[/tex] and [tex]\( P \cup Q \)[/tex].

Given:
[tex]\[ S = \{3, 4, 11, 12, 16\} \][/tex]

Using the union [tex]\( P \cup Q = \{4, 6, 7, 11, 12, 15, 20\} \)[/tex], we find the common elements with [tex]\( S \)[/tex]:
[tex]\[ S = \{3, 4, 11, 12, 16\} \][/tex]

The intersection [tex]\( S \cap (P \cup Q) \)[/tex]:
[tex]\[ \{4, 11, 12\} \][/tex]

Thus, the set that represents [tex]\( S \cap (P \cup Q) \)[/tex] is [tex]\( \{4, 11, 12\} \)[/tex].

The correct answer is:
[tex]\[ \{4, 11, 12\} \][/tex]