In a class of $30$, $18$ play cricket, $15$ play football, $8$ play both. The number who play at least one sport is:
A$25$, by $|A \cup B| = 18 + 15 - 8 = 25$ inclusion-exclusion
B$33$, summing both sports without subtracting overlap
C$30$, equal to the total students count in the class
D$8$, only the students who play both sports together
Answer & Solution
Correct answer: A. $25$, by $|A \cup B| = 18 + 15 - 8 = 25$ inclusion-exclusion
$|A \cup B| = |A| + |B| - |A \cap B| = 18 + 15 - 8 = 25$.
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