Question 46 of 480
Let P = {1, 2, u, v, w, x}; Q = {2, 3, u, v, w, 5, 6, y} and R = {2, 3, 4, v, x, y}.
Determine (P-Q) β© R
- A. {1, x}
- B. {x y}
- C. {x}
- D. ΙΈ
Correct Answer:
C
Explanation
To solve the problem, we need to determine the set operation \((P - Q) \cap R\). Let's break this down step by step.
### Step 1: Understand the Sets
We have three sets:
- \(P = \{1, 2, u, v, w, x\}\)
- \(Q = \{2, 3, u, v, w, 5, 6, y\}\)
- \(R = \{2, 3, 4, v, x, y\}\)
### Step 2: Calculate \(P - Q\)
The operation \(P - Q\) means we need to find the elements that are in set \(P\) but not in set \(Q\).
1. **List the elements of \(P\)**: \(1, 2, u, v, w, x\)
2. **Identify which of these elements are in \(Q\)**:
- \(2\) is in \(Q\)
- \(u\) is in \(Q\)
- \(v\) is in \(Q\)
- \(w\) is in \(Q\)
- \(x\) is not in \(Q\)
- \(1\) is not in \(Q\)
3. **Remove the elements of \(P\) that are in \(Q\)**:
- From \(P\), we remove \(2, u, v, w\).
- The remaining elements are \(1\) and \(x\).
Thus, we have:
\[
P - Q = \{1, x\}
\]
### Step 3: Calculate \((P - Q) \cap R\)
Now we need to find the intersection of the set \(P - Q\) with set \(R\).
1. **Identify the elements of \(P - Q\)**: \(\{1, x\}\)
2. **List the elements of \(R\)**: \(2, 3, 4, v, x, y\)
3. **Find common elements between \(\{1, x\}\) and \(R\)**:
- \(1\) is not in \(R\)
- \(x\) is in \(R\)
Thus, the intersection is:
\[
(P - Q) \cap R = \{x\}
\]
### Conclusion
The final answer is:
**C. \{x\}**
### Explanation of Other Options
- **A. \{1, x\}**: This option is incorrect because while \(x\) is indeed in the intersection, \(1\) is not in \(R\), so it cannot be part of the intersection.
- **B. \{x, y\}**: This option is incorrect because \(y\) is not in \(P - Q\) at all, so it cannot be included in the intersection.
- **D. ΙΈ (the empty set)**: This option is incorrect because we found that \(x\) is indeed in the intersection, so the intersection is not empty.
### Revision Summary
- **Set Difference**: \(P - Q\) includes elements in \(P\) that are not in \(Q\).
- **Intersection**: \((P - Q) \cap R\) includes elements common to both sets.
- **Final Result**: The intersection yielded \{x\} as the only common element.
- **Check Elements**: Always verify which elements belong to each set when performing set operations.