As today is the Ides of march I thought I'd share an old brainteaser called the "The Fermi Solution". The basic question is "When you take a single breath, how many molecules of gas you intake would have come from the dying breath of Caesar?"
Assuming that that the molecules which Caesar exhaled in his last breath have diffused evenly to the whole atmosphere and has not been converted or absorbed into other chemicals.
Here is a link with the answer.
Caesars Last Breath
