easy Probability
A release-checked easy problem for training Counting With Indicators, Linearity of Expectation, Expected Value/LOTUS, Expected Value.
$n$ heterosexual married couples (husband and wife) sit uniformly at random around a circular table of $2n$ seats. Due to seating limitations, the seats alternate between men and women. Find the expected number of couples that sit adjacent to each other when $n = 10$.
This Probability problem is tagged Counting With Indicators, Linearity of Expectation, Expected Value/LOTUS, Expected Value. State the random variables and conditioning information explicitly, then check the result against boundary cases before opening hints or a solution.
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