Random walk or binomial?? Statement: A drunk person wonders aimlessly along a path by going forward 1 step and backward 1 step with equal probabilities of ½. After 10 steps, a) what is the probability that he has moved 2 steps forward? b) What is the probability that he will make it to his front door within 20 steps before he collapses with the door being 6 steps in front of him. My approach was to use Binomial in both cases: a)10C2 (0.5)^10 b)20C6 (0.5)^20 Is that correct? I have been reading about random walk and they sometimes give another equation. (10+2)/2=6 and thn the result is like this 10C6. The result is not the same and then I start to have my doubts. Can some one please tell me if my approach using binomial distribution is right?