Are there no other sources for updated information?
I found an updated source for U.S. cities so I will updated this quiz. If you haven't looked for an updated world source, perhaps do that before unfeaturing the quiz. I will also look and let you know.
According to the source these numbers just take the 2010 to 2020 growth rate and assume that holds until 2100. I'm not sure the best way to project population in 2100, but it does not seem very plausible to me that places like Orlando and Dallas will continue seeing 20%+ growth decade over decade.
Meanwhile, Dallas and Houston are growing fast and have basically already reached their projected 2100 population.
Looks like their predictions are already comically broken.
I'll make a note to defeature that quiz.
I found an updated source for U.S. cities so I will updated this quiz. If you haven't looked for an updated world source, perhaps do that before unfeaturing the quiz. I will also look and let you know.