Destroyer quantitative reasonining help please

[CannabisWERD]

For Destroyer number 27 why is that permutation different than the one in destroyer number 20. as far as setup they have a 3! on the bottom for number 27 and there is no such factor in number 20. Same goes for questions 86, 87 and 89. None of those, like number 20, have a extra factor in the denominator, but for 27 there is that extra factor of a 3!, can someone please help me I'm so confused as to why they are set up that way. Thanks.

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