[Drupon]

It's not a trick question. It has a simple answer. It's literally impossible to specify a question about real world objects without some degree of prior knowledge about both the contents of the question and the expectation of the questioner coming into play.

The obvious answer here is 100 minutes because it's impossible to perfectly encapsulate every real life factor. What happens if a gamma ray burst destroys the machines? What happens if the machine operators go on strike? Etc, etc. The answer is 100.