Problem

Problem of the Day #93

POTD March 11, 2024

Starting with an empty string, we create a string by repeatedly appending one of the letters A, B, C with probabilities \frac{1}{4}, \frac{1}{2}, \frac{1}{4}, respectively, until the letter B appears twice consecutively. What is the expected value of the length of the resulting string?


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Problem Tags: Counting and probability

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