Riddle: A poor man is sitting in a pub. He sees that the man next to him is extremely rich.
Poor man: I have an amazing talent; I know almost every song that has ever existed.
The rich man laughs.
Poor man: I am willing to bet you all the money you have in your wallet that I can sing a popular song that includes a lady's name of your choosing.
The rich man laughs again.
Rich man: OK, how about my daughter's name, Joanna Armstrong-Miller?
The poor man goes home rich.
What song did he sing?
Answer: "Happy Birthday." This song can be sang with anybody's name in it.
Riddle: A rat is placed at the beginning of a maze and must make it to the end. There are four paths at the start that he has an equal chance of taking: path A takes 5 minutes and leads to the end, path B takes 8 minutes and leads to the start, path C takes 3 minutes and leads to the end, and path D takes 2 minutes and leads to the start.
What is the expected amount of time it will take for the rat to finish the maze?
Answer: 9 minutes.
Each path has an equal chance of occurring and if B or D are chosen they will just add 8 or 2 minutes to the time because the rat must restart the maze: time = (1/4)*5 + (1/4)*(8 + time) + (1/4)*(3) + (1/4)*(2 + time). Time = 9 minutes.