premise: What is certain, however, is that around 120,000 years ago, at least, the modern Homo sapiens first appeared and lived contemporaneously with the Neanderthal for at least 90,000 years, until the Neanderthal disappeared 30,000 years ago.
hypothesis: Homo sapiens lived at the same time as neanderthals for more than 30,000 years 
reason: They lived at the same time for at least 90,000 years, and that is more than 30,000