A selection is to be made for one post of principal and two posts of vice-principal amongst the six candidates called for the interview only two are eligible for the post of principal while they all are eligible for the post of vice-principal. The number of possible combinations of selectees is___________?
Correct answer: D. None of these
- A. 4
- B. 12
- C. 18
- D. None of these
Explanation
The principal must be chosen from the 2 eligible candidates, giving 2 choices. After that, choose 2 vice-principals from the remaining 5 candidates, giving 5C2 = 10 choices, so the total is 2 x 10 = 20. The likely mistake is 12, which does not correctly account for the available vice-principal selections after appointing the principal.
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