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About LinkBacksA brand new standard deck of 52 playing cards comes with the cards arranged in a particular order. Before using them, the cards are shuffled. What is the probability that exactly 10 of the cards will remain in their original position?
derangement question
A brand new standard deck of 52 playing cards comes with the cards arranged in a particular order. Before using them, the cards are shuffled. What is the probability that exactly 10 of the cards will remain in their original position?
Don't forget to take into account the possible choices of the 10 cards that remain in their original position.Originally Posted by Bruno J.
Clearly it's equal to the number of possible derangements of the remaining 42 cards, divided by. The number of derangements of
objects is the integer closest to
, in this case
. So the probability is
.
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