Question 1160357
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The formula (4!)/(2!) = 12 produces the correct number/answer 12;

    but the logic behind it is DARK.



The common/normal/regular logic is  

    the number of permutations of 2 items selected from a group of 4 items  is  4*3 = 12.



It says that you can place any of 4 items to the 1-st position

and then to complete the pair by adding any of 3 remaining items.
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