In a certain country, the average retirement age for college graduates

niks18 Bunuel VeritasPrepKarishma ENGRTOMBA2018


As per niks18 approach



Interestingly the question stem has a lot more information. Did you not take additional info
while analyzing the statements,


Please elaborate this a step further as to how did you know we can find ratio of x/y from this.



I believe now you have taken info from Q stem as average for retirement age for college graduates = sum of retirement ages/ total no of retirement ages
But again I am confused how can we deduce ratio x/y from this

Hey Niks,

Do we need to assume that there are only two classes of people in that country?

Question says, " Among retirees in that country, what is the ratio of college graduates to people who have not graduated from college?"

How can we assume that we have x + y = 63.1 and not x + y + z = 63.1

(2) The average retirement age in the country is 63.1.

I am confused.

a and b give 2 different ratios.

a gives 1:4 and b gives 1:3

16/48= 1/3 and not 1/4.
the 2 options give differing ratios

Hi rahulkashyap

thanks for pointing out. the question needs to be rectified.

Veritas Prep edited the question since it was first published. Now, (1) reads: 25% of retirees in the country are college graduates. (It was 20% before)

VERITAS PREP OFFICIAL SOLUTION:

Pay particular attention to the specific question being asked here: the question wants you to find a ratio, not an exact number. And weighted averages, the primary concept tested on this problem, lend themselves quite well to solving for ratios.

With statement 1, it is important to note that when categories are defined as "X" and "not X" (here that's "college graduates" and "people who have not graduated college"), that structure means that they add up to 100%. You'll see this setup in many word problems and probability problems. So when the world of retirees is divided into those two complementary categories, you know that if 25% of retirees are college graduates, then 75% are not college graduates. This then means that the ratio of college graduates to people who have not graduated from college is 1:3, and that the statement is sufficient.

With statement 2, recognize that the value supplied (63.1) is the weighted average of the retirement ages for college graduates (58.3) and people who have not graduated from college (64.7). As mentioned above, weighted averages are tailor-made for ratios. If you employ the weighted average mapping strategy, you can see that you have:

58.3-------------------63.1---------64.7
-----------4.8-----------------1.6---------

Since the distances from each individual average to the weighted average are 4.8 and 1.6, you know that the ratio between the groups is 3:1. And with the weighted average closer to "people who have not graduated from college," that group will take the larger value. The ratio, then, is 1:3.

Because both statements are sufficient to determine that 1:3 ratio, the answer is D.

Hi AkshdeepS

I have assumed: "x" college graduate retirees & "y" non graduate retirees

There could be 100s of colleges but among all the colleges the question bifurcates two types of retirees.

Let me know if you have any doubts.

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.