Disturbing the Row
Problem
Six students sit in a row of connected desks and can leave only from the two ends of the row. They finish their exams in a uniformly random order, and a student who wants to leave before someone seated between them and the nearer end must disturb those still seated. Let be the number of students in the row who disturb someone when leaving. Find .
Answer
Solution
| Difficulty | 7/10 |
|---|---|
| Topics | combinatorics, Counting, probability, Symmetry |
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