00:01
In this question, we're assuming that a drunk person wanted aimlessly along a bit.
00:07
That is either going forward one step, with probability half of some of the same probability.
00:20
So 1 minus 1.
00:21
So i want to know after 10 steps, what would be the probability that he had won't? two steps forward.
00:29
In this case, in total, we want to know the probability of getting two steps forward.
00:37
This is the same thing as checking how many possible ways can we have two step forwards when we have 10 to consider, and that is the combination.
00:49
And then we have the probability that they will step forward as half, like 0 .5, and that will happen in this case to the power of 10.
01:00
Because it is the same probability of step forward or not.
01:04
But we could have represented this as separating this to the case in which he is stepped for twice, times the probability for the rest he is stepping backward, but it's the same as this spawning 10.
01:17
Then that will be 210 over 1 ,024, which is 0 .251.
01:27
Then for b, we want to find here what is the probability that he will make to his front door, which is within 20 steps before he collapse with the door being six steps in front of him.
01:48
So in this case, what we're going to do is therefore we don't know the number of steps.
01:54
In this case, number k, so we're going to change that value...