Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Probability and random walk

  1. Sep 6, 2006 #1
    The question:

    "Two men start out together at the origin, each having a 1/2 chance of making a step to the left or right along the x-axis. Find the probability that they meet again after N steps."

    It then says it may help to consider their relative position but I don't see how that would help.

    The probability for one person is Wn(n1) = N!/[(n1!)(N-n1)!]*p^n1*q^(N-n1)

    where N is total steps, n1 is steps to the right, p = q = 1/2 (for this problem). I just don't know how to combine/adjust it for two people.

    Also, i'm not sure, but would this involve an integral from 0 to N steps at some point (to cover all cases)?
  2. jcsd
  3. Sep 6, 2006 #2
    i commented on the other post... hopfully it can help you
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook