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10 questions from this quiz
Order of selection does not matter
C(n,r)=n!r!(n−r)!C(n, r) = \frac{n!}{r!(n-r)!}C(n,r)=r!(n−r)!n!
Total number of items
Number of items to select
Product of all positive integers up to n
120120120
Order matters in permutations only
120120120 ways
300330033003 ways
When order is irrelevant
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