It's poorly phrased, but I take it to mean, "How long does a university class last?"
And that's not clear enough, either. My answer would be, "Fifty minutes or more, depending on how often it meets each week."
But it might mean, "How many weeks does a university class last?"
Either way, there's no right answer. So the most precise way to answer it is to take out a ruler and measure the length of the words "a university class." Then you'll know exactly how long "a university class" is.