 Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2025/paper-2/12/a/solution

Write

N = g + r

P (GGG) = \frac{g}{N} \frac{g - 1}{N - 1} \frac{g - 2}{N - 2} .

On this event no equality of the two colour counts has occurred, so the game's stopping rule does not interrupt these three draws.

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