Expectation · Cards · difficulty 3 of 5
Matching neighbors
A deck of 26 red and 26 black cards is shuffled so every order is equally likely, and laid out in a row. Count the neighboring pairs, the cards in positions 1 and 2, 2 and 3, and so on, where both cards are the same color. What is the expected count?
Answer with an expected value. First lock in a gut guess with an 80% range, then solve it properly, then watch a simulation settle on the truth.
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