Bunuel wrote:

The population of County X was 25,000 on January 1, 1998. During what year did its population reach 250,000?

(1) The population doubled each year.

(2) The population was 800,000 on January 1, 2003.

Statement 1- We know the rate of growth of population, hence we can calculate the year when the population hit 250,000 level. The mathematics involved is below-

Population January 1,1999=50,000

Population January 1,2000=100,000

Population January 1,2001=200,000

Population January 1,2002=400,000

Thus population level hit 250,000 in the year 2001

Statement 1 is sufficient

Statement 2- It doesn,t tell us anything. we cannot assume the rate of population increase to be uniform so as to calculate the rate of growth and then the year when population became 250,000. Not Sufficient.

Hence the answer is A