In 2000, a population of a city is one million
people. If it has a
doubling time of 25
years, when will its
population reach two
million?

The population of the city will reach 2 million people in 2025.

Explanation:

The city in question has one million people. The doubling time of the population is estimated at 25 years. Double of one million is two million, and with the population being one million in 2000, 2025 will be the year when the city will have a population of two million since the doubling time is 25 years.

s Doubling of the population in 25 years is not something that happens rarely, but it mostly happens in smaller cities or towns, as the population needed for doubling the preexisting one shouldn't be that large. A city of one million people to double its population in just 25 years is another story. Such a scenario will mean a highly centralized region, with most of the region getting depopulated, while the city in question gets a huge amount of new residents, causing a lot of urbanistic challenges.