A man takes a step forward with probability 0.4 and backwards with probability 0.6 Find the probability that at the end of eleven steps he is just one step away from the starting point?

Answer 1

1. He takes 6 steps forward and 5 steps backward

2. He takes 5 steps forward and 6 steps backward

consider 1:

p1 = (11C6)(0.4)^6*(0.6)^5

for 2:

p2 = 11C5(0.4)^5*(0.6)^6

total probability = p1 + p2