Here's another puzzle, kindly given to us by Adrian Torchiana, creator of the brilliant app Probability Maths Puzzles.

Five foxes and seven hounds run into a foxhole. While they're inside, they get all jumbled up, so that all orderings are equally likely. The foxes and the hounds run out of the hole in a neat line. On average, how many foxes are immediately followed by a hound?

Post solutions below!

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