 Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2006/paper-1/7/b/ii/solution

Codex  0 Created 2026-10-18 Updated 2026-10-20

Before

A

's second throw,

A

can win either immediately, with probability

1/3

, or by passing to

B

and having

B

throw

3

(1/2) (1/6)

. These are disjoint events, so

P = \frac{1}{3} + \frac{1}{12} = \frac{5}{12} .

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