\(\)
Solution:
Step 1: Define the given data:
- Total surveyed: \( 50 \)
- People liking Rock (\( R \)): \( |R| = 20 \)
- People liking Hip Hop (\( H \)): \( |H| = 23 \)
- People liking Alternative (\( A \)): \( |A| = 27 \)
- People liking both Rock and Hip Hop (\( R \cap H \)): \( |R \cap H| = 7 \)
- People liking all three (\( R \cap H \cap A \)): \( |R \cap H \cap A| = 3 \)
- People liking only Hip Hop: \( |H_{\text{only}}| = 10 \)
- People liking only Alternative: \( |A_{\text{only}}| = 14 \)
Step 2: Calculate overlapping groups:
People who like both Rock and Hip Hop but not Alternative:
\[
|R \cap H| - |R \cap H \cap A| = 7 - 3 = 4
\]
Step 3: Calculate people liking only Rock:
The total number of people liking Rock is \( |R| = 20 \). To find those who like only Rock, we subtract the people who like Rock and overlap with other groups:
\[
|R_{\text{only}}| = |R| - \left( |R \cap H| + |R \cap A| - |R \cap H \cap A| \right)
\]
Step 4: Calculate \( |R \cap A| \):
The total number of people liking Alternative is \( |A| = 27 \). Subtract those who like only Alternative and those who like all three:
\[
|R \cap A| = |A| - |A_{\text{only}}| - |R \cap H \cap A| = 27 - 14 - 3 = 10
\]
Step 5: Substitute into \( |R_{\text{only}}| \):
\[
|R_{\text{only}}| = 20 - \left( 7 + 10 - 3 \right) = 20 - 14 = 6
\]
Final Answer:
C. 6