To find the probability that a student chosen at random is over 15 or plays basketball, we can use the principle of inclusion-exclusion.
Let's define:
- \( A \) = the event that a student is over 15
- \( B \) = the event that a student plays basketball
First, we need to find \( P(A) \), \( P(B) \), and \( P(A \cap B) \):
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Total number of students, \( N \): 123
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Number of students over 15, \( |A| \): 79
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Number of students playing basketball, \( |B| \): 32
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Number of students over 15 who play basketball, \( |A \cap B| \): 24
Now, we can calculate the probabilities:
- \( P(A) = \frac{|A|}{N} = \frac{79}{123} \)
- \( P(B) = \frac{|B|}{N} = \frac{32}{123} \)
- \( P(A \cap B) = \frac{|A \cap B|}{N} = \frac{24}{123} \)
Using the principle of inclusion-exclusion: \[ P(A \cup B) = P(A) + P(B) - P(A \cap B) \] Substituting the values: \[ P(A \cup B) = \frac{79}{123} + \frac{32}{123} - \frac{24}{123} \] Now, combine the fractions: \[ P(A \cup B) = \frac{79 + 32 - 24}{123} = \frac{87}{123} \]
Thus, the probability that a student chosen at random is over 15 or plays basketball is: \[ \frac{87}{123} \]
The final answer is: \(\frac{87}{123}\)