The question:(adsbygoogle = window.adsbygoogle || []).push({});

"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-n2)

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)?

edit: I have posted this in the math section as it is more relevant

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Probability and random walk

**Physics Forums | Science Articles, Homework Help, Discussion**