Payout from blue beating red by three before a tie
Question
A red and a blue fair ten-sided die (faces –) are rolled together repeatedly. When the two match, the game stops. Otherwise, if blue exceeds red by or more you earn $1, and in every non-matching case you roll again. What is your expected total winnings?
Short answer
. Per round, a tie has probability and a paying outcome (red allows blue values, ). The number of rounds is geometric, so expected earnings are .
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Open the worked solutionLessons behind this question
- Random Variables and Probability Mass Functions
- Counting and Combinatorics
- Expectation, Mean, and Variance
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