Assume that you are on the ground floor of a building with 100 floors. You have a dice with 6 faces with the number 1 to 6 on the faces. You are playing a game, you will be the winner if you can reach the 60th floor or higher. The way you go is:
You roll the dice:
The result is 1 or 2 then you go down 1 floor. The result is from 3 to 5, you go up 1 floor. If the result is 6, you can roll again, the you will go up the number of floor as the number you get. You can go 1oo times.
Notice:
For some reason, you need to go back to the ground floor. this -probability for this 0.1%. No negative floor, It means that if you are on the ground floor, and you roll the 1 or 2 faces, you will be still on the ground floor. Calculate the probability of the winning?
Many assumptions make me confuse. I don't know how to deal with the assumption "For some reason, you need to go back to the ground floor. this -probability for this 0.1%"