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AMO 2021 - Secondary 4 (Grade 10) Question 23

AMO · AMO 2021 - Secondary 4 (Grade 10)

Question 23

A bug starts at the lower-left corner of the square. Trap 1 is at the upper-right corner, and Trap 2 at the lower-right corner. At each untrapped corner, the bug chooses each of its two adjacent sides with probability $1/2$ and moves to the next corner. It stops on reaching a trap. If $p$ is the probability it is caught at Trap 2, find $60p$.

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