The population of City X doubles every 25 years. If this rate continues for the foreseeable future, how many centuries will it take for the population to increase from 20,000 to 1,280,000?

A. 6
B. 4.5
C. 2.5
D. 2
E. 1.5
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1,280,000/20,000 = 64 times = 2^6 times

25*6 = 150 years = 1.5 centuries

Answer: E

We are given that the population of City X doubles every 25 years. We need to determine the number of centuries it will take the population to increase from 20,000 to 1,280,000.

We can start by making a list (or table) that keeps track of doubling the population every 25 years:

Current: 20,000
After 25 years: 40,000
After 50 years: 80,000
After 75 years: 160,000
After 100 years: 320,000
After 125 years: 640,000
After 150 years: 1,280,000

Thus it takes 150 years, or 1.5 centuries, to increase the population from 20,000 to 1,280,000.

Answer: E
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