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Why is n!/(k!(n-k)!) the count of k-combinations?
AOrderings of both groups are removed
BFactorials are always even numbers
CRepeated items are counted twice
DEach object is used exactly twice
Answer & Solution
Correct answer: A. Orderings of both groups are removed
The n! orderings overcount each selection by k! orderings of the chosen and (n - k)! of the rest.
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