7. Edge of Escape II
Setup
A traveler stands in a dark corridor.
Each step, he moves left or right with equal probability.
Rules
- 10 steps left: cliff (death)
- 15 steps right: exit (safety)
Question
What is the probability that he survives?
Answer format
Enter a number rounded to 2 decimal places.
Your Answer
Need help?
Hint 1
This is a generalization of Edge of Escape I. The same approach works but with different boundary positions.
Hint 2
For a symmetric random walk with absorbing boundaries, the survival probability is linear in position.
Hint 3
If cliff is at -a and exit at +b, what is the general formula for survival probability from position 0?