My roommate works at Google and usually gets home around 11:00 PM every night. During the week, all she does is work and walking two blocks from the Google bus stop to our house is usually uneventful.

Last night she found $100 bill on the ground while walking home and I wanted to address the likelihood of that ever happening again.

1) Someone has to be walking and her path with $100 bills that night.

2) That someone has to drop the $100 bill and not notice.

3) She has to be the first person to see the $100 bill.

4) She had to have gotten off work at that exact time with the buses running at that exact speed.

So let’s recap…

1) The chances of people walking around with $100 bills. We live in San Francisco and people are rich, so I’ll say it happens all the time. 1:2

2) The chances of someone dropping the $100 bill in our neighborhood… Probably only happens maybe once every five years. So multiply 1825 by the number of people walking around with $100 bills per day, let’s just say its 10. 1:18,250

3) Being the first person to notice is also very unlikely considering we live in a crowded city. Let’s just say if we put a $100 on her path around the same time everyday for the next year, she probably wouldn’t be the first. 1:365

4) The window of opportunity was probably 2-3 minutes. So I think you can take the number of times she has gotten home within that 2-3 minute range. This will also account for the timing of the person dropping the $100 bill because he/she has to drop the bill at that exact time and location. So let’s say its 1:25.

1 and 333,062,500… which is pretty close to winning the lottery. Has anyone else randomly found a $100 bill on the street?