The cards of a standard 52-card deck are dealt out in a circle. What is the expected number of pairs of adjacent cards which are both black? Express your answer as a common fraction.
For each pair of cards, the probability that they are both black is 2652∗2551=25102, so since there are 52 pairs in the circle, the expected number of pairs which are both black is 25102∗52=65051.
+127 
