Difficulty: Easy
Correct Answer: 25/39
Explanation:
Introduction / Context:
“At least one” probability questions are usually simpler via complement: subtract the probability that no one satisfies the property from 1. Here, “no woman” means both selected are men.
Given Data / Assumptions:
Concept / Approach:
P(≥1 woman) = 1 − P(both men) = 1 − C(8,2)/C(13,2).
Step-by-Step Solution:
C(8,2) = 28; C(13,2) = 78.P(≥1 woman) = 1 − 28/78 = 50/78 = 25/39.
Verification / Alternative check:
Direct count of favourable outcomes: total pairs (78) minus all-men pairs (28) = 50 favourable → 50/78 = 25/39.
Why Other Options Are Wrong:
10/13 and 5/13 arise from incorrect linear approximations; 14/35 is unrelated.
Common Pitfalls:
Forgetting to use combinations (unordered selection) or to apply the complement method.
Final Answer:
25/39
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