Need some help in understanding how to solve this GRE question.

Question

Question: The population of a country increases at a fixed percentage each year.

Column A: Increase in population in the first decade $1980-1990$.

Column B: Increase in population in the second decade $1990-2000$.

It is a quantitative comparison question, i.e, I have to compare Column A with Column B. IF Col A > Col B the answer is A. If Col A < Col B the answer is B, if both equal then the answer is C, and if there is not enough information to compare them, then the answer is D.

My answer at first was (C) i.e. both columns are equal, but Column B is greater than Column A is the correct answer.

So why is the correct answer B? That is, Column B > Column A.

@tpb261 Which part of the question do u feel is not complete? — OGC, May 26 '14 at 06:06
@user36829: You haven't stated what the question is actually asking. Not everyone knows the format of GRE math questions; it's not clear that you're supposed to be comparing the two quantities. — user2357112, May 26 '14 at 06:07
@ThomasAndrews Thanks for pointing that out. I will make an edit soon. — OGC, May 26 '14 at 06:11

score 2 · Accepted Answer · answered May 26 '14 at 06:09

Let's say the population increases by 10% a year, and at the start of 1980, it had exactly 1 million people in it.

In the year 1980, the population increases by 10% of 1 million. By the end, there are 1.1 million people in the country.

In the year 1981, the population increases by 10% of 1.1 million. By the end, there are 1.21 million people in the country.

The population grows more in later years, because it's growing by the same percentage of a larger number.

Yeah it seems quite easy actually. I had misread the question the first time. — OGC, May 26 '14 at 06:36

Need some help in understanding how to solve this GRE question.

1 Answers1