200.Passing a Hundred With a Four-Sided Die
★★★random walksJane Street
A fair four-sided die numbered 1 to 4 is rolled repeatedly and the results are added to a running total. What is the expected value of the first total that exceeds 100?
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The answer is 100 plus the expected overshoot. In the long run the overshoot distribution settles down and no longer depends on the exact threshold.
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