The answer to the first unknown is "40 years" while in the second unknown the answer is "500 years". Such as to complete the statement in the problem we have it like, at the current rates of growth, it will take a least industrialized nation 40 years to double its population and 500 years for the average most industrialized nation to double its population. As we could see in the data, the economic and financial status of the region has a great contribution and a factor in the rates of its growing population.
