Think of the first round as fixed.
In the second round, each of the 5 candidates is again assigned to the 5 managers, one candidate per manager. Thus the second round corresponds to a permutation of the 5 candidates.
A manager interviews the same candidate in both rounds iff that manager is a
fixed point of the permutation.
The question asks for the probability that
exactly 3 managers interviewed more than one candidate.
Since each manager interviews exactly one candidate in each round:
- If a manager gets the same candidate both times, they interviewed only 1 distinct candidate.
- If a manager gets a different candidate in round 2, they interviewed 2 distinct candidates.
Therefore, "interviewed more than one candidate" means
not a fixed point.
Exactly 3 managers interviewed more than one candidate
⇒ exactly 2 managers interviewed the same candidate both rounds
⇒ the permutation has exactly 2 fixed points.
Total permutations of 5 candidates:
5! = 120
Count permutations with exactly 2 fixed points:
- Choose the 2 fixed points:
C(5,2) = 10 - The remaining 3 candidates must have no fixed points (a derangement of 3).
Number of derangements of 3:
!3 = 2
Thus favorable permutations:
10 × 2 = 20
Probability:
20 / 120 = 1/6
Answer:
E. 1/6.